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| Electronic Schematics (alt.binaries.schematics.electronic) A place to show and share your electronics schematic drawings. |
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#1
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Sample & hold - for frequency.
What would be the minimalist circuit blocks for a frequency domain sample
and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. It occurs to me that there might be a PLL in there somewhere, but I've got blank sheet of paper syndrome. TIA. |
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#2
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Sample & hold - for frequency.
On Wed, 4 Nov 2009 13:17:24 -0000, "ian field"
wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. It occurs to me that there might be a PLL in there somewhere, but I've got blank sheet of paper syndrome. TIA. Tape loop ?:-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice  480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!" |
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#3
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Sample & hold - for frequency.
Jim Thompson wrote: On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. It occurs to me that there might be a PLL in there somewhere, but I've got blank sheet of paper syndrome. TIA. Tape loop ?:-) A well trained mocking bird? ;-) -- The movie 'Deliverance' isn't a documentary! |
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#4
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Sample & hold - for frequency.
"ian field" wrote in message ... What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. It occurs to me that there might be a PLL in there somewhere, but I've got blank sheet of paper syndrome. TIA. The Boss DF-2 pedal does something like that. See http://www.schematicx.com/view-schem...dal-schematic/ for example. Chris |
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#5
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Sample & hold - for frequency.
On Wed, 4 Nov 2009 13:17:24 -0000, "ian field"
wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? JF |
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#6
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Sample & hold - for frequency.
On Wed, 04 Nov 2009 10:34:20 -0600, John Fields
wrote: On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? JF Wasn't there at one time something called a "bucket brigade" that could take snap-shot recordings? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Calling an illegal alien an "undocumented immigrant" is like Calling a drug dealer an "unlicensed pharmacist" |
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#7
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Sample & hold - for frequency.
Jim Thompson wrote: On Wed, 04 Nov 2009 10:34:20 -0600, John Fields wrote: On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? JF Wasn't there at one time something called a "bucket brigade" that could take snap-shot recordings? Digikey was still selling the Panasonic 'Bucket Brigade Analog Delay Lines' a few years ago. -- The movie 'Deliverance' isn't a documentary! |
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#8
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Sample & hold - for frequency.
On Wed, 04 Nov 2009 13:58:37 -0500, "Michael A. Terrell"
wrote: Jim Thompson wrote: On Wed, 04 Nov 2009 10:34:20 -0600, John Fields wrote: On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? JF Wasn't there at one time something called a "bucket brigade" that could take snap-shot recordings? Digikey was still selling the Panasonic 'Bucket Brigade Analog Delay Lines' a few years ago. Of course, the best response to the OP is, "WHY?" ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!" |
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#9
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Sample & hold - for frequency.
On Wed, 04 Nov 2009 12:39:06 -0700, Jim Thompson
wrote: On Wed, 04 Nov 2009 13:58:37 -0500, "Michael A. Terrell" wrote: Jim Thompson wrote: On Wed, 04 Nov 2009 10:34:20 -0600, John Fields wrote: On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? JF Wasn't there at one time something called a "bucket brigade" that could take snap-shot recordings? Digikey was still selling the Panasonic 'Bucket Brigade Analog Delay Lines' a few years ago. Of course, the best response to the OP is, "WHY?" --- I don't much care about why, since the fun for me is doing the design. :-) Seems what the OP wants to do is monitor a sine wave source and then when the source's tone gets to some "threshold", have the device monitoring the source generate that tone forever. But, who knows for sure, since his "specs" were pretty sketchy? JF |
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#10
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Sample & hold - for frequency.
On Wed, 04 Nov 2009 15:24:10 -0600, John Fields
wrote: On Wed, 04 Nov 2009 12:39:06 -0700, Jim Thompson wrote: On Wed, 04 Nov 2009 13:58:37 -0500, "Michael A. Terrell" wrote: Jim Thompson wrote: On Wed, 04 Nov 2009 10:34:20 -0600, John Fields wrote: On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? JF Wasn't there at one time something called a "bucket brigade" that could take snap-shot recordings? Digikey was still selling the Panasonic 'Bucket Brigade Analog Delay Lines' a few years ago. Of course, the best response to the OP is, "WHY?" --- I don't much care about why, since the fun for me is doing the design. :-) Seems what the OP wants to do is monitor a sine wave source and then when the source's tone gets to some "threshold", have the device monitoring the source generate that tone forever. But, who knows for sure, since his "specs" were pretty sketchy? JF Indeed! Is the frequency always the same value? Or a variety of frequencies? Why not a simple tone detector? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!" |
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#11
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Sample & hold - for frequency.
On Wed, 04 Nov 2009 15:24:10 -0600, John Fields
wrote: On Wed, 04 Nov 2009 12:39:06 -0700, Jim Thompson wrote: On Wed, 04 Nov 2009 13:58:37 -0500, "Michael A. Terrell" wrote: Jim Thompson wrote: On Wed, 04 Nov 2009 10:34:20 -0600, John Fields wrote: On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? JF Wasn't there at one time something called a "bucket brigade" that could take snap-shot recordings? Digikey was still selling the Panasonic 'Bucket Brigade Analog Delay Lines' a few years ago. Of course, the best response to the OP is, "WHY?" --- I don't much care about why, since the fun for me is doing the design. :-) Seems what the OP wants to do is monitor a sine wave source and then when the source's tone gets to some "threshold", have the device monitoring the source generate that tone forever. But, who knows for sure, since his "specs" were pretty sketchy? JF Indeed! Is the frequency always the same value? Or a variety of frequencies? Why not a simple tone detector? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!" |
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#12
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
"John Fields" wrote in message ... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. |
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#13
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
"Jim Thompson" wrote in message ... On Wed, 04 Nov 2009 15:24:10 -0600, John Fields wrote: On Wed, 04 Nov 2009 12:39:06 -0700, Jim Thompson wrote: On Wed, 04 Nov 2009 13:58:37 -0500, "Michael A. Terrell" wrote: Jim Thompson wrote: On Wed, 04 Nov 2009 10:34:20 -0600, John Fields wrote: On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? JF Wasn't there at one time something called a "bucket brigade" that could take snap-shot recordings? Digikey was still selling the Panasonic 'Bucket Brigade Analog Delay Lines' a few years ago. Of course, the best response to the OP is, "WHY?" --- I don't much care about why, since the fun for me is doing the design. :-) Seems what the OP wants to do is monitor a sine wave source and then when the source's tone gets to some "threshold", have the device monitoring the source generate that tone forever. But, who knows for sure, since his "specs" were pretty sketchy? JF Indeed! Is the frequency always the same value? Or a variety of frequencies? Why not a simple tone detector? If it was only one frequency I could just build a sound activated oscillator. |
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#14
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
On Wed, 4 Nov 2009 22:11:38 -0000, "ian field"
wrote: "Jim Thompson" wrote in message ... On Wed, 04 Nov 2009 15:24:10 -0600, John Fields wrote: On Wed, 04 Nov 2009 12:39:06 -0700, Jim Thompson wrote: On Wed, 04 Nov 2009 13:58:37 -0500, "Michael A. Terrell" wrote: Jim Thompson wrote: On Wed, 04 Nov 2009 10:34:20 -0600, John Fields wrote: On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? JF Wasn't there at one time something called a "bucket brigade" that could take snap-shot recordings? Digikey was still selling the Panasonic 'Bucket Brigade Analog Delay Lines' a few years ago. Of course, the best response to the OP is, "WHY?" --- I don't much care about why, since the fun for me is doing the design. :-) Seems what the OP wants to do is monitor a sine wave source and then when the source's tone gets to some "threshold", have the device monitoring the source generate that tone forever. But, who knows for sure, since his "specs" were pretty sketchy? JF Indeed! Is the frequency always the same value? Or a variety of frequencies? Why not a simple tone detector? If it was only one frequency I could just build a sound activated oscillator. Why do you need to continue the tone? Range of allowed input frequencies? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!" |
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#15
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
On Wed, 4 Nov 2009 22:11:38 -0000, "ian field"
wrote: "Jim Thompson" wrote in message ... On Wed, 04 Nov 2009 15:24:10 -0600, John Fields wrote: On Wed, 04 Nov 2009 12:39:06 -0700, Jim Thompson wrote: On Wed, 04 Nov 2009 13:58:37 -0500, "Michael A. Terrell" wrote: Jim Thompson wrote: On Wed, 04 Nov 2009 10:34:20 -0600, John Fields wrote: On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? JF Wasn't there at one time something called a "bucket brigade" that could take snap-shot recordings? Digikey was still selling the Panasonic 'Bucket Brigade Analog Delay Lines' a few years ago. Of course, the best response to the OP is, "WHY?" --- I don't much care about why, since the fun for me is doing the design. :-) Seems what the OP wants to do is monitor a sine wave source and then when the source's tone gets to some "threshold", have the device monitoring the source generate that tone forever. But, who knows for sure, since his "specs" were pretty sketchy? JF Indeed! Is the frequency always the same value? Or a variety of frequencies? Why not a simple tone detector? If it was only one frequency I could just build a sound activated oscillator. If you sample the incoming waveform, then store it in a shift-register, doesn't that give you what you want? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!" |
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#16
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Sample & hold - for frequency.
On Wed, 4 Nov 2009 22:09:04 -0000, "ian field"
wrote: "John Fields" wrote in message .. . On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. JF |
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#17
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Sample & hold - for frequency.
On Wed, 4 Nov 2009 22:09:04 -0000, "ian field"
wrote: "John Fields" wrote in message .. . On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. JF |
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#18
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Sample & hold - for frequency.
"John Fields" wrote in message ... On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message . .. On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. |
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#19
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Sample & hold - for frequency.
On Thu, 5 Nov 2009 16:20:21 -0000, "ian field"
wrote: "John Fields" wrote in message .. . On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message ... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF |
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#20
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Sample & hold - for frequency.
On Thu, 05 Nov 2009 11:12:46 -0600, John Fields
wrote: On Thu, 5 Nov 2009 16:20:21 -0000, "ian field" wrote: "John Fields" wrote in message . .. On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message m... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!" |
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#21
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Sample & hold - for frequency.
On Thu, 05 Nov 2009 10:18:07 -0700, Jim Thompson
wrote: [snip] Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. ...Jim Thompson Make that [and "zero-crossing" conditions are _met_] ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!" |
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#22
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Sample & hold - for frequency.
"Jim Thompson" wrote in message ... On Thu, 05 Nov 2009 11:12:46 -0600, John Fields wrote: On Thu, 5 Nov 2009 16:20:21 -0000, "ian field" wrote: "John Fields" wrote in message ... On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message om... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. You've got part of it, the piano in question is electronic with PWM note generation so selecting church organ voice, while giving a sustained note - gives a DFC reading of about 12kHz for any note. To solve that problem a mic is to be used instead of connecting to the output jack, I want to measure the frequencies that different instrument voices assign to the keys - church organ is the only voice that has sustain. |
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#23
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Sample & hold - for frequency.
Jim Thompson wrote:
On Wed, 04 Nov 2009 15:24:10 -0600, John Fields wrote: On Wed, 04 Nov 2009 12:39:06 -0700, Jim Thompson wrote: On Wed, 04 Nov 2009 13:58:37 -0500, "Michael A. Terrell" wrote: Jim Thompson wrote: On Wed, 04 Nov 2009 10:34:20 -0600, John Fields wrote: On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? JF Wasn't there at one time something called a "bucket brigade" that could take snap-shot recordings? Digikey was still selling the Panasonic 'Bucket Brigade Analog Delay Lines' a few years ago. Of course, the best response to the OP is, "WHY?" --- I don't much care about why, since the fun for me is doing the design. :-) Seems what the OP wants to do is monitor a sine wave source and then when the source's tone gets to some "threshold", have the device monitoring the source generate that tone forever. But, who knows for sure, since his "specs" were pretty sketchy? JF Indeed! Is the frequency always the same value? Or a variety of frequencies? Why not a simple tone detector? ...Jim Thompson A PLL with a really low offset, linear phase detector a is a good approximation--when the signal goes away, the loop essentially opens without any big transient. A normal T/H on the VCO control voltage would be a nice extra touch. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal ElectroOptical Innovations 55 Orchard Rd Briarcliff Manor NY 10510 845-480-2058 hobbs at electrooptical dot net http://electrooptical.net |
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#24
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
On Thu, 5 Nov 2009 17:56:35 -0000, "ian field"
wrote: "Jim Thompson" wrote in message ... On Thu, 05 Nov 2009 11:12:46 -0600, John Fields wrote: On Thu, 5 Nov 2009 16:20:21 -0000, "ian field" wrote: "John Fields" wrote in message m... On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message news:14b3f59r96io1hnj8bmets5hnhs09tu0b3@4ax. com... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. You've got part of it, the piano in question is electronic with PWM note generation so selecting church organ voice, while giving a sustained note - gives a DFC reading of about 12kHz for any note. To solve that problem a mic is to be used instead of connecting to the output jack, I want to measure the frequencies that different instrument voices assign to the keys - church organ is the only voice that has sustain. --- I'm not familiar with PWM note generation. How does it work? JF |
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#25
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
On Thu, 05 Nov 2009 17:59:36 -0600, John Fields
wrote: On Thu, 5 Nov 2009 17:56:35 -0000, "ian field" wrote: "Jim Thompson" wrote in message ... On Thu, 05 Nov 2009 11:12:46 -0600, John Fields wrote: On Thu, 5 Nov 2009 16:20:21 -0000, "ian field" wrote: "John Fields" wrote in message om... On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message news:14b3f59r96io1hnj8bmets5hnhs09tu0b3@4ax .com... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. You've got part of it, the piano in question is electronic with PWM note generation so selecting church organ voice, while giving a sustained note - gives a DFC reading of about 12kHz for any note. To solve that problem a mic is to be used instead of connecting to the output jack, I want to measure the frequencies that different instrument voices assign to the keys - church organ is the only voice that has sustain. --- I'm not familiar with PWM note generation. How does it work? JF Class-D or similar. I'm surprised the "carrier" is only 12kHz... seems low. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!" |
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#26
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
On Thu, 05 Nov 2009 18:55:49 -0600, flipper wrote:
On Thu, 05 Nov 2009 17:11:31 -0700, Jim Thompson wrote: On Thu, 05 Nov 2009 17:59:36 -0600, John Fields wrote: On Thu, 5 Nov 2009 17:56:35 -0000, "ian field" wrote: "Jim Thompson" wrote in message ... On Thu, 05 Nov 2009 11:12:46 -0600, John Fields wrote: On Thu, 5 Nov 2009 16:20:21 -0000, "ian field" wrote: "John Fields" wrote in message news:9n24f5tikm8h0aaq6m04sgf58b2mdfkagf@4ax .com... On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message news:14b3f59r96io1hnj8bmets5hnhs09tu0b3@4 ax.com... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. You've got part of it, the piano in question is electronic with PWM note generation so selecting church organ voice, while giving a sustained note - gives a DFC reading of about 12kHz for any note. To solve that problem a mic is to be used instead of connecting to the output jack, I want to measure the frequencies that different instrument voices assign to the keys - church organ is the only voice that has sustain. --- I'm not familiar with PWM note generation. How does it work? JF Class-D or similar. I'm surprised the "carrier" is only 12kHz... seems low. Well, according to this page http://www.electricdruid.net/index.p...e=info.hammond the highest generated harmonic on a Hammond is 5924.62Hz so, in theory, it's enough. ...Jim Thompson That's certainly pushing Shannon to the test ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!" |
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#27
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
On Thu, 05 Nov 2009 19:12:05 -0600, flipper wrote:
On Thu, 05 Nov 2009 18:06:07 -0700, Jim Thompson wrote: On Thu, 05 Nov 2009 18:55:49 -0600, flipper wrote: On Thu, 05 Nov 2009 17:11:31 -0700, Jim Thompson wrote: On Thu, 05 Nov 2009 17:59:36 -0600, John Fields wrote: [snip] I'm not familiar with PWM note generation. How does it work? JF Class-D or similar. I'm surprised the "carrier" is only 12kHz... seems low. Well, according to this page http://www.electricdruid.net/index.p...e=info.hammond the highest generated harmonic on a Hammond is 5924.62Hz so, in theory, it's enough. ...Jim Thompson That's certainly pushing Shannon to the test ;-) Hehe. Yeah. On the other hand, maybe that particular organ doesn't produce the same harmonics or maybe they figured no one would notice the upper harmonic missing on notes that high up the scale. ...Jim Thompson Doesn't it equate, church goers == old farts ?:-) I've haven't been able to hear a flyback for many a year... maybe as far back as my late 40's. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | Obama says, "I AM NOT a cry baby, Fox REALLY IS out to get me!" |
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#28
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
On Thu, 5 Nov 2009 17:56:35 -0000, "ian field"
wrote: "Jim Thompson" wrote in message ... On Thu, 05 Nov 2009 11:12:46 -0600, John Fields wrote: On Thu, 5 Nov 2009 16:20:21 -0000, "ian field" wrote: "John Fields" wrote in message m... On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message news:14b3f59r96io1hnj8bmets5hnhs09tu0b3@4ax. com... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. You've got part of it, the piano in question is electronic with PWM note generation so selecting church organ voice, while giving a sustained note - gives a DFC reading of about 12kHz for any note. To solve that problem a mic is to be used instead of connecting to the output jack, I want to measure the frequencies that different instrument voices assign to the keys - church organ is the only voice that has sustain. --- I'm surprised; I would have thought all of the non-percussion instruments would have sustain. Just as an aside, for _any_ of the voices, determining the frequency of a single note will yield the frequency of all the rest since the octave is equally tempered and the difference between neighboring notes goes as the 12th root of 2. Assuming that your mic can integrate out the 12kHz transitions and yield a harmonic and overtone-free fundamental, what I'd do would be to detect sequential zero crossings of the signal, square them up with a comparator, and use the time between the edges to allow a counter chain to accumulate high frequency clocks (the frequency of the clock chosen to force the regenerated signal (the "copy") to yield the accuracy you need) then, at the end of that time, to latch that value and send the output of the latch to the broadside load inputs of the counter chain. Simultaneously, the counter chain's count direction will be changed, making it a down counter, and when it gets to zero it'll clock a dflop wired as a divide-by-two, and will also reload the value stored in the latch into the counter, starting the cycle anew. The net result will be that the output frequency of the divide-by-two will mimic the output frequency of the synthesizer. JF |
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#29
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
"flipper" wrote in message ... On Thu, 05 Nov 2009 18:06:07 -0700, Jim Thompson wrote: On Thu, 05 Nov 2009 18:55:49 -0600, flipper wrote: On Thu, 05 Nov 2009 17:11:31 -0700, Jim Thompson wrote: On Thu, 05 Nov 2009 17:59:36 -0600, John Fields wrote: On Thu, 5 Nov 2009 17:56:35 -0000, "ian field" wrote: "Jim Thompson" wrote in message ... On Thu, 05 Nov 2009 11:12:46 -0600, John Fields wrote: On Thu, 5 Nov 2009 16:20:21 -0000, "ian field" wrote: "John Fields" wrote in message news:9n24f5tikm8h0aaq6m04sgf58b2mdfkagf@4 ax.com... On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message news:14b3f59r96io1hnj8bmets5hnhs09tu0b3 @4ax.com... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. You've got part of it, the piano in question is electronic with PWM note generation so selecting church organ voice, while giving a sustained note - gives a DFC reading of about 12kHz for any note. To solve that problem a mic is to be used instead of connecting to the output jack, I want to measure the frequencies that different instrument voices assign to the keys - church organ is the only voice that has sustain. --- I'm not familiar with PWM note generation. How does it work? JF Class-D or similar. I'm surprised the "carrier" is only 12kHz... seems low. Well, according to this page http://www.electricdruid.net/index.p...e=info.hammond the highest generated harmonic on a Hammond is 5924.62Hz so, in theory, it's enough. ...Jim Thompson That's certainly pushing Shannon to the test ;-) Hehe. Yeah. On the other hand, maybe that particular organ doesn't produce the same harmonics or maybe they figured no one would notice the upper harmonic missing on notes that high up the scale. Its a pretty old Casio, only 4 note polyphonic IIRC. |
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#30
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
"John Fields" wrote in message ... On Thu, 5 Nov 2009 17:56:35 -0000, "ian field" wrote: "Jim Thompson" wrote in message ... On Thu, 05 Nov 2009 11:12:46 -0600, John Fields wrote: On Thu, 5 Nov 2009 16:20:21 -0000, "ian field" wrote: "John Fields" wrote in message om... On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message news:14b3f59r96io1hnj8bmets5hnhs09tu0b3@4ax .com... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. You've got part of it, the piano in question is electronic with PWM note generation so selecting church organ voice, while giving a sustained note - gives a DFC reading of about 12kHz for any note. To solve that problem a mic is to be used instead of connecting to the output jack, I want to measure the frequencies that different instrument voices assign to the keys - church organ is the only voice that has sustain. --- I'm surprised; I would have thought all of the non-percussion instruments would have sustain. Just as an aside, for _any_ of the voices, determining the frequency of a single note will yield the frequency of all the rest since the octave is equally tempered and the difference between neighboring notes goes as the 12th root of 2. Assuming that your mic can integrate out the 12kHz transitions and yield a harmonic and overtone-free fundamental, what I'd do would be to detect sequential zero crossings of the signal, square them up with a comparator, and use the time between the edges to allow a counter chain to accumulate high frequency clocks (the frequency of the clock chosen to force the regenerated signal (the "copy") to yield the accuracy you need) then, at the end of that time, to latch that value and send the output of the latch to the broadside load inputs of the counter chain. Simultaneously, the counter chain's count direction will be changed, making it a down counter, and when it gets to zero it'll clock a dflop wired as a divide-by-two, and will also reload the value stored in the latch into the counter, starting the cycle anew. The net result will be that the output frequency of the divide-by-two will mimic the output frequency of the synthesizer. JF I was hoping for something pretty minimalist - its a sort of one hit project that once its given me the info I want, its likely to get robbed of parts for later projects. Many years ago I wrote a program in basic to sequence every possible combination of lottery numbers and identify all the bell curve numbers, the program took a week and a day to examine each of the 14M possible combinations and terminate on a 12MHz 286. it was only used once to give me the range of numbers I wanted. |
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#31
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
"John Fields" wrote in message ... On Thu, 5 Nov 2009 17:56:35 -0000, "ian field" wrote: "Jim Thompson" wrote in message ... On Thu, 05 Nov 2009 11:12:46 -0600, John Fields wrote: On Thu, 5 Nov 2009 16:20:21 -0000, "ian field" wrote: "John Fields" wrote in message om... On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message news:14b3f59r96io1hnj8bmets5hnhs09tu0b3@4ax .com... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. You've got part of it, the piano in question is electronic with PWM note generation so selecting church organ voice, while giving a sustained note - gives a DFC reading of about 12kHz for any note. To solve that problem a mic is to be used instead of connecting to the output jack, I want to measure the frequencies that different instrument voices assign to the keys - church organ is the only voice that has sustain. --- I'm surprised; I would have thought all of the non-percussion instruments would have sustain. Just as an aside, for _any_ of the voices, determining the frequency of a single note will yield the frequency of all the rest since the octave is equally tempered and the difference between neighboring notes goes as the 12th root of 2. Assuming that your mic can integrate out the 12kHz transitions and yield a harmonic and overtone-free fundamental, what I'd do would be to detect sequential zero crossings of the signal, square them up with a comparator, and use the time between the edges to allow a counter chain to accumulate high frequency clocks (the frequency of the clock chosen to force the regenerated signal (the "copy") to yield the accuracy you need) then, at the end of that time, to latch that value and send the output of the latch to the broadside load inputs of the counter chain. Simultaneously, the counter chain's count direction will be changed, making it a down counter, and when it gets to zero it'll clock a dflop wired as a divide-by-two, and will also reload the value stored in the latch into the counter, starting the cycle anew. The net result will be that the output frequency of the divide-by-two will mimic the output frequency of the synthesizer. JF I was hoping for something pretty minimalist - its a sort of one hit project that once its given me the info I want, its likely to get robbed of parts for later projects. Many years ago I wrote a program in basic to sequence every possible combination of lottery numbers and identify all the bell curve numbers, the program took a week and a day to examine each of the 14M possible combinations and terminate on a 12MHz 286. it was only used once to give me the range of numbers I wanted. |
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#32
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
On Fri, 6 Nov 2009 14:53:26 -0000, "ian field"
wrote: "John Fields" wrote in message .. . Assuming that your mic can integrate out the 12kHz transitions and yield a harmonic and overtone-free fundamental, what I'd do would be to detect sequential zero crossings of the signal, square them up with a comparator, and use the time between the edges to allow a counter chain to accumulate high frequency clocks (the frequency of the clock chosen to force the regenerated signal (the "copy") to yield the accuracy you need) then, at the end of that time, to latch that value and send the output of the latch to the broadside load inputs of the counter chain. Simultaneously, the counter chain's count direction will be changed, making it a down counter, and when it gets to zero it'll clock a dflop wired as a divide-by-two, and will also reload the value stored in the latch into the counter, starting the cycle anew. The net result will be that the output frequency of the divide-by-two will mimic the output frequency of the synthesizer. JF I was hoping for something pretty minimalist - its a sort of one hit project that once its given me the info I want, its likely to get robbed of parts for later projects. --- Well, you're going to need, as a minimum, something which you can use to measure the period of the waveform and then read it out and take its reciprocal. That could be something as simple as a comparator, a dflop, an RS flip-flop, a clock source, and a counter feeding some LEDs Just for grins, let's say the highest frequency you can get out of the organ is 3520 Hz (A7) and you want to measure the frequency to +/- 1%. In order to do that you'll need a clock running 100 times faster, which is 352000 Hz., and something to accumulate 100 clock cycles during one 3520 Hz. cycle; an 8 bit binary up counter. So what you'd do would be to manually reset the counter, have the first rising edge of the squared-up organ signal enable the counter, and the next rising edge disable it forever. Then you'd get the contents of the counter by reading the LEDs, and the frequency of the organ signal by multiplying the counter's contents by 284.0909µs and taking the reciprocal of the product. One thing to be aware of is that as the frequency of the organ signal decreases, either the length of the counter will have to increase or the frequency of the clock decrease in order to prevent overflow. Finally, it could get tricky trying to catch the first real rising edge of the organ signal, so what I'd do would be to insert a small (10ms?) delay from the whatever the rising thing out of mic was and, when it timed out, use the next 2 rising edges to gate the counter, JF |
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#33
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
On Fri, 6 Nov 2009 14:53:26 -0000, "ian field"
wrote: "John Fields" wrote in message .. . Assuming that your mic can integrate out the 12kHz transitions and yield a harmonic and overtone-free fundamental, what I'd do would be to detect sequential zero crossings of the signal, square them up with a comparator, and use the time between the edges to allow a counter chain to accumulate high frequency clocks (the frequency of the clock chosen to force the regenerated signal (the "copy") to yield the accuracy you need) then, at the end of that time, to latch that value and send the output of the latch to the broadside load inputs of the counter chain. Simultaneously, the counter chain's count direction will be changed, making it a down counter, and when it gets to zero it'll clock a dflop wired as a divide-by-two, and will also reload the value stored in the latch into the counter, starting the cycle anew. The net result will be that the output frequency of the divide-by-two will mimic the output frequency of the synthesizer. JF I was hoping for something pretty minimalist - its a sort of one hit project that once its given me the info I want, its likely to get robbed of parts for later projects. --- Well, you're going to need, as a minimum, something which you can use to measure the period of the waveform and then read it out and take its reciprocal. That could be something as simple as a comparator, a dflop, an RS flip-flop, a clock source, and a counter feeding some LEDs Just for grins, let's say the highest frequency you can get out of the organ is 3520 Hz (A7) and you want to measure the frequency to +/- 1%. In order to do that you'll need a clock running 100 times faster, which is 352000 Hz., and something to accumulate 100 clock cycles during one 3520 Hz. cycle; an 8 bit binary up counter. So what you'd do would be to manually reset the counter, have the first rising edge of the squared-up organ signal enable the counter, and the next rising edge disable it forever. Then you'd get the contents of the counter by reading the LEDs, and the frequency of the organ signal by multiplying the counter's contents by 284.0909µs and taking the reciprocal of the product. One thing to be aware of is that as the frequency of the organ signal decreases, either the length of the counter will have to increase or the frequency of the clock decrease in order to prevent overflow. Finally, it could get tricky trying to catch the first real rising edge of the organ signal, so what I'd do would be to insert a small (10ms?) delay from the whatever the rising thing out of mic was and, when it timed out, use the next 2 rising edges to gate the counter, JF |
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#34
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
"flipper" wrote in message ... On Fri, 6 Nov 2009 14:42:39 -0000, "ian field" wrote: "flipper" wrote in message . .. On Thu, 05 Nov 2009 18:06:07 -0700, Jim Thompson wrote: On Thu, 05 Nov 2009 18:55:49 -0600, flipper wrote: On Thu, 05 Nov 2009 17:11:31 -0700, Jim Thompson wrote: On Thu, 05 Nov 2009 17:59:36 -0600, John Fields wrote: On Thu, 5 Nov 2009 17:56:35 -0000, "ian field" wrote: "Jim Thompson" wrote in message ... On Thu, 05 Nov 2009 11:12:46 -0600, John Fields wrote: On Thu, 5 Nov 2009 16:20:21 -0000, "ian field" wrote: "John Fields" wrote in message news:9n24f5tikm8h0aaq6m04sgf58b2mdfkagf @4ax.com... On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message news:14b3f59r96io1hnj8bmets5hnhs09tu0 ... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. You've got part of it, the piano in question is electronic with PWM note generation so selecting church organ voice, while giving a sustained note - gives a DFC reading of about 12kHz for any note. To solve that problem a mic is to be used instead of connecting to the output jack, I want to measure the frequencies that different instrument voices assign to the keys - church organ is the only voice that has sustain. --- I'm not familiar with PWM note generation. How does it work? JF Class-D or similar. I'm surprised the "carrier" is only 12kHz... seems low. Well, according to this page http://www.electricdruid.net/index.p...e=info.hammond the highest generated harmonic on a Hammond is 5924.62Hz so, in theory, it's enough. ...Jim Thompson That's certainly pushing Shannon to the test ;-) Hehe. Yeah. On the other hand, maybe that particular organ doesn't produce the same harmonics or maybe they figured no one would notice the upper harmonic missing on notes that high up the scale. Its a pretty old Casio, only 4 note polyphonic IIRC. Have you tried looking up the model number? Just for fun I downloaded all the casio manuals - none of the 3 or 4 models that have fallen into my possession over the years was among them. |
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#35
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
"flipper" wrote in message ... On Fri, 6 Nov 2009 14:42:39 -0000, "ian field" wrote: "flipper" wrote in message . .. On Thu, 05 Nov 2009 18:06:07 -0700, Jim Thompson wrote: On Thu, 05 Nov 2009 18:55:49 -0600, flipper wrote: On Thu, 05 Nov 2009 17:11:31 -0700, Jim Thompson wrote: On Thu, 05 Nov 2009 17:59:36 -0600, John Fields wrote: On Thu, 5 Nov 2009 17:56:35 -0000, "ian field" wrote: "Jim Thompson" wrote in message ... On Thu, 05 Nov 2009 11:12:46 -0600, John Fields wrote: On Thu, 5 Nov 2009 16:20:21 -0000, "ian field" wrote: "John Fields" wrote in message news:9n24f5tikm8h0aaq6m04sgf58b2mdfkagf @4ax.com... On Wed, 4 Nov 2009 22:09:04 -0000, "ian field" wrote: "John Fields" wrote in message news:14b3f59r96io1hnj8bmets5hnhs09tu0 ... On Wed, 4 Nov 2009 13:17:24 -0000, "ian field" wrote: What would be the minimalist circuit blocks for a frequency domain sample and hold? What I envisage is the sampling triggered by a tone that exceeds a pre-set threshold and continues to generate a copy of the tone until reset. --- I'm confused... What do you mean by 'sampling' and what do you mean by 'threshold'? Sample a frequency - the analogy with "sample and hold" is once the frequency is recognised, something like a VCO continues to reproduce the frequency until a reset. Threshold is when a tone exceeds a set amplitude it triggers the sample action, so as to prevent background sounds confusing the circuit. --- OK, that's doable. Next, do you need the copy to be a sine wave, like the original, or can it be a square wave Also, what kind of frequency/phase accuracy are you looking for with regard to the difference between the source and the copy? What else can you tell us? Voltages, power, etc, etc. You know, the details the devil's in. Its for feeding a digital frequency counter, so it can be converted to a square wave at any point in the process. The objective is for a frequency range equal to all the keys on a piano, it needs to be fairly accurate. --- There may be a much simpler way to solve whatever problem you need the gadget for. What's your application? JF Sounds like piano tuning... he hits a key, and wants "sustain" (while he counts it ??) He'd be better off starting a high speed counter when both amplitude and "zero-crossing" conditions are and measure period. Then invert to get frequency. You've got part of it, the piano in question is electronic with PWM note generation so selecting church organ voice, while giving a sustained note - gives a DFC reading of about 12kHz for any note. To solve that problem a mic is to be used instead of connecting to the output jack, I want to measure the frequencies that different instrument voices assign to the keys - church organ is the only voice that has sustain. --- I'm not familiar with PWM note generation. How does it work? JF Class-D or similar. I'm surprised the "carrier" is only 12kHz... seems low. Well, according to this page http://www.electricdruid.net/index.p...e=info.hammond the highest generated harmonic on a Hammond is 5924.62Hz so, in theory, it's enough. ...Jim Thompson That's certainly pushing Shannon to the test ;-) Hehe. Yeah. On the other hand, maybe that particular organ doesn't produce the same harmonics or maybe they figured no one would notice the upper harmonic missing on notes that high up the scale. Its a pretty old Casio, only 4 note polyphonic IIRC. Have you tried looking up the model number? Just for fun I downloaded all the casio manuals - none of the 3 or 4 models that have fallen into my possession over the years was among them. |
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#36
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
"John Fields" wrote in message news  On Fri, 6 Nov 2009 14:53:26 -0000, "ian field" wrote: "John Fields" wrote in message . .. Assuming that your mic can integrate out the 12kHz transitions and yield a harmonic and overtone-free fundamental, what I'd do would be to detect sequential zero crossings of the signal, square them up with a comparator, and use the time between the edges to allow a counter chain to accumulate high frequency clocks (the frequency of the clock chosen to force the regenerated signal (the "copy") to yield the accuracy you need) then, at the end of that time, to latch that value and send the output of the latch to the broadside load inputs of the counter chain. Simultaneously, the counter chain's count direction will be changed, making it a down counter, and when it gets to zero it'll clock a dflop wired as a divide-by-two, and will also reload the value stored in the latch into the counter, starting the cycle anew. The net result will be that the output frequency of the divide-by-two will mimic the output frequency of the synthesizer. JF I was hoping for something pretty minimalist - its a sort of one hit project that once its given me the info I want, its likely to get robbed of parts for later projects. --- Well, you're going to need, as a minimum, something which you can use to measure the period of the waveform and then read it out and take its reciprocal. That could be something as simple as a comparator, a dflop, an RS flip-flop, a clock source, and a counter feeding some LEDs Just for grins, let's say the highest frequency you can get out of the organ is 3520 Hz (A7) and you want to measure the frequency to +/- 1%. In order to do that you'll need a clock running 100 times faster, which is 352000 Hz., and something to accumulate 100 clock cycles during one 3520 Hz. cycle; an 8 bit binary up counter. So what you'd do would be to manually reset the counter, have the first rising edge of the squared-up organ signal enable the counter, and the next rising edge disable it forever. Then you'd get the contents of the counter by reading the LEDs, and the frequency of the organ signal by multiplying the counter's contents by 284.0909µs and taking the reciprocal of the product. One thing to be aware of is that as the frequency of the organ signal decreases, either the length of the counter will have to increase or the frequency of the clock decrease in order to prevent overflow. Finally, it could get tricky trying to catch the first real rising edge of the organ signal, so what I'd do would be to insert a small (10ms?) delay from the whatever the rising thing out of mic was and, when it timed out, use the next 2 rising edges to gate the counter, JF Can't I just make a PLL lock on to the frequency and stay put after the note has decayed, then measure the frequency with a digital frequency counter? |
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#37
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
"John Fields" wrote in message news On Fri, 6 Nov 2009 14:53:26 -0000, "ian field" wrote: "John Fields" wrote in message . .. Assuming that your mic can integrate out the 12kHz transitions and yield a harmonic and overtone-free fundamental, what I'd do would be to detect sequential zero crossings of the signal, square them up with a comparator, and use the time between the edges to allow a counter chain to accumulate high frequency clocks (the frequency of the clock chosen to force the regenerated signal (the "copy") to yield the accuracy you need) then, at the end of that time, to latch that value and send the output of the latch to the broadside load inputs of the counter chain. Simultaneously, the counter chain's count direction will be changed, making it a down counter, and when it gets to zero it'll clock a dflop wired as a divide-by-two, and will also reload the value stored in the latch into the counter, starting the cycle anew. The net result will be that the output frequency of the divide-by-two will mimic the output frequency of the synthesizer. JF I was hoping for something pretty minimalist - its a sort of one hit project that once its given me the info I want, its likely to get robbed of parts for later projects. --- Well, you're going to need, as a minimum, something which you can use to measure the period of the waveform and then read it out and take its reciprocal. That could be something as simple as a comparator, a dflop, an RS flip-flop, a clock source, and a counter feeding some LEDs Just for grins, let's say the highest frequency you can get out of the organ is 3520 Hz (A7) and you want to measure the frequency to +/- 1%. In order to do that you'll need a clock running 100 times faster, which is 352000 Hz., and something to accumulate 100 clock cycles during one 3520 Hz. cycle; an 8 bit binary up counter. So what you'd do would be to manually reset the counter, have the first rising edge of the squared-up organ signal enable the counter, and the next rising edge disable it forever. Then you'd get the contents of the counter by reading the LEDs, and the frequency of the organ signal by multiplying the counter's contents by 284.0909µs and taking the reciprocal of the product. One thing to be aware of is that as the frequency of the organ signal decreases, either the length of the counter will have to increase or the frequency of the clock decrease in order to prevent overflow. Finally, it could get tricky trying to catch the first real rising edge of the organ signal, so what I'd do would be to insert a small (10ms?) delay from the whatever the rising thing out of mic was and, when it timed out, use the next 2 rising edges to gate the counter, JF Can't I just make a PLL lock on to the frequency and stay put after the note has decayed, then measure the frequency with a digital frequency counter? |
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#38
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
On Fri, 6 Nov 2009 20:53:53 -0000, "ian field"
wrote: "John Fields" wrote in message news On Fri, 6 Nov 2009 14:53:26 -0000, "ian field" wrote: "John Fields" wrote in message ... Assuming that your mic can integrate out the 12kHz transitions and yield a harmonic and overtone-free fundamental, what I'd do would be to detect sequential zero crossings of the signal, square them up with a comparator, and use the time between the edges to allow a counter chain to accumulate high frequency clocks (the frequency of the clock chosen to force the regenerated signal (the "copy") to yield the accuracy you need) then, at the end of that time, to latch that value and send the output of the latch to the broadside load inputs of the counter chain. Simultaneously, the counter chain's count direction will be changed, making it a down counter, and when it gets to zero it'll clock a dflop wired as a divide-by-two, and will also reload the value stored in the latch into the counter, starting the cycle anew. The net result will be that the output frequency of the divide-by-two will mimic the output frequency of the synthesizer. JF I was hoping for something pretty minimalist - its a sort of one hit project that once its given me the info I want, its likely to get robbed of parts for later projects. --- Well, you're going to need, as a minimum, something which you can use to measure the period of the waveform and then read it out and take its reciprocal. That could be something as simple as a comparator, a dflop, an RS flip-flop, a clock source, and a counter feeding some LEDs Just for grins, let's say the highest frequency you can get out of the organ is 3520 Hz (A7) and you want to measure the frequency to +/- 1%. In order to do that you'll need a clock running 100 times faster, which is 352000 Hz., and something to accumulate 100 clock cycles during one 3520 Hz. cycle; an 8 bit binary up counter. So what you'd do would be to manually reset the counter, have the first rising edge of the squared-up organ signal enable the counter, and the next rising edge disable it forever. Then you'd get the contents of the counter by reading the LEDs, and the frequency of the organ signal by multiplying the counter's contents by 284.0909µs and taking the reciprocal of the product. One thing to be aware of is that as the frequency of the organ signal decreases, either the length of the counter will have to increase or the frequency of the clock decrease in order to prevent overflow. Finally, it could get tricky trying to catch the first real rising edge of the organ signal, so what I'd do would be to insert a small (10ms?) delay from the whatever the rising thing out of mic was and, when it timed out, use the next 2 rising edges to gate the counter, JF Can't I just make a PLL lock on to the frequency and stay put after the note has decayed, then measure the frequency with a digital frequency counter? A PLL that doesn't drift once it loses reference ?:-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice 480)460-2350 Fax: Available upon request | Brass Rat || E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
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#39
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
"Jim Thompson" wrote in message news On Fri, 6 Nov 2009 20:53:53 -0000, "ian field" wrote: "John Fields" wrote in message news On Fri, 6 Nov 2009 14:53:26 -0000, "ian field" wrote: "John Fields" wrote in message m... Assuming that your mic can integrate out the 12kHz transitions and yield a harmonic and overtone-free fundamental, what I'd do would be to detect sequential zero crossings of the signal, square them up with a comparator, and use the time between the edges to allow a counter chain to accumulate high frequency clocks (the frequency of the clock chosen to force the regenerated signal (the "copy") to yield the accuracy you need) then, at the end of that time, to latch that value and send the output of the latch to the broadside load inputs of the counter chain. Simultaneously, the counter chain's count direction will be changed, making it a down counter, and when it gets to zero it'll clock a dflop wired as a divide-by-two, and will also reload the value stored in the latch into the counter, starting the cycle anew. The net result will be that the output frequency of the divide-by-two will mimic the output frequency of the synthesizer. JF I was hoping for something pretty minimalist - its a sort of one hit project that once its given me the info I want, its likely to get robbed of parts for later projects. --- Well, you're going to need, as a minimum, something which you can use to measure the period of the waveform and then read it out and take its reciprocal. That could be something as simple as a comparator, a dflop, an RS flip-flop, a clock source, and a counter feeding some LEDs Just for grins, let's say the highest frequency you can get out of the organ is 3520 Hz (A7) and you want to measure the frequency to +/- 1%. In order to do that you'll need a clock running 100 times faster, which is 352000 Hz., and something to accumulate 100 clock cycles during one 3520 Hz. cycle; an 8 bit binary up counter. So what you'd do would be to manually reset the counter, have the first rising edge of the squared-up organ signal enable the counter, and the next rising edge disable it forever. Then you'd get the contents of the counter by reading the LEDs, and the frequency of the organ signal by multiplying the counter's contents by 284.0909µs and taking the reciprocal of the product. One thing to be aware of is that as the frequency of the organ signal decreases, either the length of the counter will have to increase or the frequency of the clock decrease in order to prevent overflow. Finally, it could get tricky trying to catch the first real rising edge of the organ signal, so what I'd do would be to insert a small (10ms?) delay from the whatever the rising thing out of mic was and, when it timed out, use the next 2 rising edges to gate the counter, JF Can't I just make a PLL lock on to the frequency and stay put after the note has decayed, then measure the frequency with a digital frequency counter? A PLL that doesn't drift once it loses reference ?:-) It only needs to stay put for just over a second to cover the gate time of the counter. |
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#40
Posted to alt.binaries.schematics.electronic
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Sample & hold - for frequency.
On Fri, 6 Nov 2009 20:53:53 -0000, "ian field"
wrote: "John Fields" wrote in message news On Fri, 6 Nov 2009 14:53:26 -0000, "ian field" wrote: "John Fields" wrote in message ... Assuming that your mic can integrate out the 12kHz transitions and yield a harmonic and overtone-free fundamental, what I'd do would be to detect sequential zero crossings of the signal, square them up with a comparator, and use the time between the edges to allow a counter chain to accumulate high frequency clocks (the frequency of the clock chosen to force the regenerated signal (the "copy") to yield the accuracy you need) then, at the end of that time, to latch that value and send the output of the latch to the broadside load inputs of the counter chain. Simultaneously, the counter chain's count direction will be changed, making it a down counter, and when it gets to zero it'll clock a dflop wired as a divide-by-two, and will also reload the value stored in the latch into the counter, starting the cycle anew. The net result will be that the output frequency of the divide-by-two will mimic the output frequency of the synthesizer. JF I was hoping for something pretty minimalist - its a sort of one hit project that once its given me the info I want, its likely to get robbed of parts for later projects. --- Well, you're going to need, as a minimum, something which you can use to measure the period of the waveform and then read it out and take its reciprocal. That could be something as simple as a comparator, a dflop, an RS flip-flop, a clock source, and a counter feeding some LEDs Just for grins, let's say the highest frequency you can get out of the organ is 3520 Hz (A7) and you want to measure the frequency to +/- 1%. In order to do that you'll need a clock running 100 times faster, which is 352000 Hz., and something to accumulate 100 clock cycles during one 3520 Hz. cycle; an 8 bit binary up counter. So what you'd do would be to manually reset the counter, have the first rising edge of the squared-up organ signal enable the counter, and the next rising edge disable it forever. Then you'd get the contents of the counter by reading the LEDs, and the frequency of the organ signal by multiplying the counter's contents by 284.0909µs and taking the reciprocal of the product. One thing to be aware of is that as the frequency of the organ signal decreases, either the length of the counter will have to increase or the frequency of the clock decrease in order to prevent overflow. Finally, it could get tricky trying to catch the first real rising edge of the organ signal, so what I'd do would be to insert a small (10ms?) delay from the whatever the rising thing out of mic was and, when it timed out, use the next 2 rising edges to gate the counter, JF Can't I just make a PLL lock on to the frequency and stay put after the note has decayed, then measure the frequency with a digital frequency counter? --- What Jim said.  In a word, no. JF |
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