Is my LT44 transformer suitable for audio (de)coupling?
 

In article , "Phil Allison" wrote:

"GregS"

** Drivel.

DC drift is due to temp variations.

It is separate from noise

NO No NO. Look at it on a scope. Look at the charts.


** Noise is noise - not drift.

You ignored all my other points so I guess you have no clue what the ****
you are on about.

If you want to isolate thermal drift, fine. I mostly talking
about visable noise fluctuating up and down over
seconds and tenths of seconds. Thats Noise.

greg

Is my LT44 transformer suitable for audio (de)coupling?
 

"GregS" = A ****WIT


** Drivel.

DC drift is due to temp variations.

It is separate from noise

NO No NO. Look at it on a scope. Look at the charts.


** Noise is noise - not drift.

You ignored all my other points so I guess you have no clue what the ****
you are on about.

If you want to isolate thermal drift, fine. I mostly talking
about visable noise fluctuating up and down over
seconds and tenths of seconds. Thats Noise.


** ROTFLMAO.

Make up you mind, you dumb ASSHOLE !!



......... Phil

Is my LT44 transformer suitable for audio (de)coupling?
 

In article , "Phil Allison" wrote:

"GregS" = A ****WIT


** Drivel.

DC drift is due to temp variations.

It is separate from noise

NO No NO. Look at it on a scope. Look at the charts.


** Noise is noise - not drift.

You ignored all my other points so I guess you have no clue what the ****
you are on about.

If you want to isolate thermal drift, fine. I mostly talking
about visable noise fluctuating up and down over
seconds and tenths of seconds. Thats Noise.


** ROTFLMAO.

Make up you mind, you dumb ASSHOLE !!


I made up my mind a long time ago.

greg

Is my LT44 transformer suitable for audio (de)coupling?
 

Don Pearce wrote:

On Mon, 01 May 2006 13:58:50 GMT, (GregS) wrote:

In article , wrote:

2 GHz at 12 GHz is 16.67% which is narrow. Don't tell me that there
is no filtering at all. A circulator or isolator has a usable bandwidth
which keeps out of band noise out of the amp. One of my KU band
receivers is aboard the ISS.

Audio is true broadband, from DC to whatever the upper limit is set
at by the design and limitations of the components if it is DC coupled,
and from less than 100 Hz if its AC coupled.

Not only that, but at low to DC freqs., the noise increases dramatically
of most devices. When looking at op-amps I have to often look at DC drifts,
which is the largest noise.

greg

Tell me about it. I've had to design baffling into a system before now
to control air currents that were causing cyclic temperature drifts.
Generally in an audio amp, though, there is sufficient DC feedback to
render this a non-problem.

d

--
Pearce Consulting
http://www.pearce.uk.com


In our analog receivers the DC offset was measured, and a 18 bit ADC
was used to trim the offset to keep it to about a millivolt from
wherever it was set. Some external decoding required a fixed DC offset,
and this was available from the front panel. We also had a 63 dB range
in the output level control, digital with accurate .1 dB steps. This
was on the Microdyne 700 and 1620/1670 series telemetry receiving
equipment.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Is my LT44 transformer suitable for audio (de)coupling?
 

GregS wrote:

Not only that, but at low to DC freqs., the noise increases dramatically
of most devices. When looking at op-amps I have to often look at DC drifts,
which is the largest noise.

greg


Tell me about it. ;-) The diversity combiner took the linear 0 to 5
VDC AGC signals to combine the two video signals into a single signal
with a fixed output level as the received levels changed. The AGC
system in the combiner had to have under 1.5 mV error after the 14 op
amps used to set levels and feed them through the venerable MC1496 used
as an analog multiplier.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Is my LT44 transformer suitable for audio (de)coupling?
 

On Mon, 01 May 2006 16:26:57 GMT, "Michael A. Terrell"
wrote:

Don Pearce wrote:

On Mon, 01 May 2006 13:58:50 GMT, (GregS) wrote:

In article , wrote:

2 GHz at 12 GHz is 16.67% which is narrow. Don't tell me that there
is no filtering at all. A circulator or isolator has a usable bandwidth
which keeps out of band noise out of the amp. One of my KU band
receivers is aboard the ISS.

Audio is true broadband, from DC to whatever the upper limit is set
at by the design and limitations of the components if it is DC coupled,
and from less than 100 Hz if its AC coupled.

Not only that, but at low to DC freqs., the noise increases dramatically
of most devices. When looking at op-amps I have to often look at DC drifts,
which is the largest noise.

greg

Tell me about it. I've had to design baffling into a system before now
to control air currents that were causing cyclic temperature drifts.
Generally in an audio amp, though, there is sufficient DC feedback to
render this a non-problem.

d

--
Pearce Consulting
http://www.pearce.uk.com


In our analog receivers the DC offset was measured, and a 18 bit ADC
was used to trim the offset to keep it to about a millivolt from
wherever it was set. Some external decoding required a fixed DC offset,
and this was available from the front panel. We also had a 63 dB range
in the output level control, digital with accurate .1 dB steps. This
was on the Microdyne 700 and 1620/1670 series telemetry receiving
equipment.

Mine was the error amplifier in an ultra low noise RF synthesiser. The
low frequency drift that resulted from the air currents resulted in
phase noise from the oscillator in the .01 to 1Hz range. It was really
hard to fault find.

d

--
Pearce Consulting
http://www.pearce.uk.com

Is my LT44 transformer suitable for audio (de)coupling?
 

Don Pearce wrote:

On Mon, 01 May 2006 13:50:43 GMT, "Michael A. Terrell"
wrote:

Don Pearce wrote:

On Mon, 01 May 2006 13:24:48 GMT, "Michael A. Terrell"
wrote:

Don Pearce wrote:

Thank you! I did make a gaffe. The actual figure for the Neve noise
figure is about 3dB. That is still unforgivably poor for high end kit
- it is in fact no better than my little Behringer. Ten years ago I
was designing satellite receivers working up at 12GHz. The noise
figure I was working to was 0.3dB.


Its a lot easier to reduce the noise figure at a narrow bandwidth at
microwave frequencies.

Narrow bandwidth? I don't call a bandwidth of nearly 2GHz narrow. And
asitappens, I can achieve these sorts of figure at audio as well.

d

--
Pearce Consulting
http://www.pearce.uk.com

2 GHz at 12 GHz is 16.67% which is narrow. Don't tell me that there
is no filtering at all. A circulator or isolator has a usable bandwidth
which keeps out of band noise out of the amp. One of my KU band
receivers is aboard the ISS.

Of course there is filtering. The waveguide coupler as a bandwidth, as
does the mixer. The image filter then has a bandwidth, and finally the
IF amplifier. Despite all this filtering - none of which is lossless -
the noise figure still happens. It really isn't easy even compared to
audio. Well done for having a receiver aboard ISS, but ground
transmitters tend not to be particularly power-limited, so the noise
figure probably isn't quite the issue it is with a terrestrial
receiver. In fact there would be no point because it is pointing at
the earth, which is hot.

Audio is true broadband, from DC to whatever the upper limit is set
at by the design and limitations of the components if it is DC coupled,
and from less than 100 Hz if its AC coupled.

But achieving low noise at audio - however you want to describe its
bandwidth - is actually pretty trivial. The fact is that manufacturers
choose not to implement it because they can make something that is
"reasonable" for a lot less money. The business of achieving low noise
at audio doesn't rely on being able to juggle S parameters, physical
layout, board materials and mechanical design like microwave.


My point about microwave is that without filtering you have aditional
noise to deal with in the system. We offered IF bandwidths from 10 KHz
to 20 MHz, and video amps with matching bandwidths to keep as much noise
out of the received signal as possible.


The same receivers are used by NOAA for their weather sat downlinks.
With the improved doppler compensation they are able to lock onto the
sat before it comes over the hrizon five minutes faster than the old
Harris equipment it replaced.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Is my LT44 transformer suitable for audio (de)coupling?
 

On Mon, 01 May 2006 17:24:30 GMT, "Michael A. Terrell"
wrote:

My point about microwave is that without filtering you have aditional
noise to deal with in the system. We offered IF bandwidths from 10 KHz
to 20 MHz, and video amps with matching bandwidths to keep as much noise
out of the received signal as possible.


The same receivers are used by NOAA for their weather sat downlinks.
With the improved doppler compensation they are able to lock onto the
sat before it comes over the hrizon five minutes faster than the old
Harris equipment it replaced.

Ah! I see what you mean. Of course matching a receive filter to the
necessary bandwidth means that you neither lose much-needed signal,
nor let in unwanted noise. That goes for IF and baseband. As for RF,
presumably you have a range of input frequencies to deal with, so you
can't implement a channel-width filter there. But what you can do is a
roofing filter and image filters.

I presume your Doppler compensation was predictive, offsetting the
receiver by 17000MPH worth of frequency in anticipation of
acquisition.

d

--
Pearce Consulting
http://www.pearce.uk.com

Is my LT44 transformer suitable for audio (de)coupling?
 

In article , wrote:
Don Pearce wrote:

On Mon, 01 May 2006 13:58:50 GMT, (GregS) wrote:

In article ,
wrote:

2 GHz at 12 GHz is 16.67% which is narrow. Don't tell me that there
is no filtering at all. A circulator or isolator has a usable bandwidth
which keeps out of band noise out of the amp. One of my KU band
receivers is aboard the ISS.

Audio is true broadband, from DC to whatever the upper limit is set
at by the design and limitations of the components if it is DC coupled,
and from less than 100 Hz if its AC coupled.

Not only that, but at low to DC freqs., the noise increases dramatically
of most devices. When looking at op-amps I have to often look at DC drifts,
which is the largest noise.

greg

Tell me about it. I've had to design baffling into a system before now
to control air currents that were causing cyclic temperature drifts.
Generally in an audio amp, though, there is sufficient DC feedback to
render this a non-problem.

d

--
Pearce Consulting
http://www.pearce.uk.com


In our analog receivers the DC offset was measured, and a 18 bit ADC
was used to trim the offset to keep it to about a millivolt from
wherever it was set. Some external decoding required a fixed DC offset,
and this was available from the front panel. We also had a 63 dB range
in the output level control, digital with accurate .1 dB steps. This
was on the Microdyne 700 and 1620/1670 series telemetry receiving
equipment.

I forget how this got into this, but I once built a 20 bit, well I don't know how many
bits, but I overlapped two 12 bit stages, and used discrets like a successive
approximation register, and op-amps and got at least 20 bit offset correction.
A/D D/A, but was interesting.

greg

Is my LT44 transformer suitable for audio (de)coupling?
 

Don Pearce wrote:

On Mon, 01 May 2006 17:24:30 GMT, "Michael A. Terrell"
wrote:

My point about microwave is that without filtering you have aditional
noise to deal with in the system. We offered IF bandwidths from 10 KHz
to 20 MHz, and video amps with matching bandwidths to keep as much noise
out of the received signal as possible.


The same receivers are used by NOAA for their weather sat downlinks.
With the improved doppler compensation they are able to lock onto the
sat before it comes over the hrizon five minutes faster than the old
Harris equipment it replaced.

Ah! I see what you mean. Of course matching a receive filter to the
necessary bandwidth means that you neither lose much-needed signal,
nor let in unwanted noise. That goes for IF and baseband. As for RF,
presumably you have a range of input frequencies to deal with, so you
can't implement a channel-width filter there. But what you can do is a
roofing filter and image filters.

I presume your Doppler compensation was predictive, offsetting the
receiver by 17000MPH worth of frequency in anticipation of
acquisition.


A lot is still covered under several NDAs I had to sign, but the rest
of it was making the system as phase clean as frequency stable as
possible. Without that, the additional circuitry didn't stand a chance.
There are only a few things you can do to compensate for the doppler
effect, but that added to careful design and implementation works
wonders. I also worked on the both the fixed and mobile earth station
for Italy's space efforts. My title was production and engineering test
tech, but a lot of the engineers ask why I didn't have a degree due to
the way I not only found problems, but how to correct them. I got
bounced all over the Ocala facility, where ever the current hot spots
were. My boss told me that I wouldn't take "NO" for an answer. I
smiled and told him, "I don't take YES if I don't believe them. ;-)


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Is my LT44 transformer suitable for audio (de)coupling?
 

Don Pearce wrote:

On Mon, 01 May 2006 16:26:57 GMT, "Michael A. Terrell"
wrote:

In our analog receivers the DC offset was measured, and a 18 bit ADC
was used to trim the offset to keep it to about a millivolt from
wherever it was set. Some external decoding required a fixed DC offset,
and this was available from the front panel. We also had a 63 dB range
in the output level control, digital with accurate .1 dB steps. This
was on the Microdyne 700 and 1620/1670 series telemetry receiving
equipment.

Mine was the error amplifier in an ultra low noise RF synthesiser. The
low frequency drift that resulted from the air currents resulted in
phase noise from the oscillator in the .01 to 1Hz range. It was really
hard to fault find.


I had to clean up an older design RF synthesizer because of multiple
engineering changes and parts going obsolete. The unit was inside a
double shield, so it was quite temperature stable, but the uncased
ceramic disk capacitor they originally used as standoffs was no longer
available. They switched to a good quality microwave ceramic capacitor,
and soldered them next to the large vias that were originally used to
solder the caps to the board. This caused the phase noise to go through
the roof. The fix was simple. Solder the holes closed, then solder the
cap where it was in the original design. The PLL was broken into three
band segments to reduce noise, and forward biased diodes were used to
short out part of the inductor to raise the frequency. The rest of the
phase noise was from the two RF output amps ringing due to a minor
change in the layout. I was working to use a Maxim IC to replace the
two amps when I was laid off in Sept. 2001. I can't remember the number
right now, but the two outputs were 180 out of phase to reduce the
current load variations. I also made some changes to the reference
frequency traps to clean up the DC loop control voltage.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Is my LT44 transformer suitable for audio (de)coupling?
 

"Phil Allison" wrote in
:

Audio band white noise is totally dominated by high frequency noise !!


White noise has equal amounts of all frequencies. We hear the HF dominate
because higher frequencies have more energy. (And because our ears are more
sensitive to it).

Is my LT44 transformer suitable for audio (de)coupling?
 

In article 0, Lostgallifreyan wrote:
"Phil Allison" wrote in
:

Audio band white noise is totally dominated by high frequency noise !!


White noise has equal amounts of all frequencies. We hear the HF dominate
because higher frequencies have more energy. (And because our ears are more
sensitive to it).

The noise voltage of many op-amps is almost flat from 1K to 100K, but below 1 K
it moves upward. I'm looking at the LF353 as it has a very low level of low frequency
noise, or at least the chart shows that. The AD711 has 18 nvHz at 1 kHz but
60 nvHz at 1 Hz.


greg

Is my LT44 transformer suitable for audio (de)coupling?
 

On Tue, 2 May 2006 00:20:04 +1000, "Phil Allison"
wrote:


"Dave Plowman (News)"


Narrow bandwidth? I don't call a bandwidth of nearly 2GHz narrow.

Don't these things tend to be measured in octaves, as it were?


** Bandwidth in *electronics* is normally quoted in Hz, kHz, MHz, GHz etc.

Octaves are a musical notion, so not used much outside of audio and
acoustics.




....... Phil



An octave is a doubling of the frequency, so it has logarithmic
implications.

Tom

Is my LT44 transformer suitable for audio (de)coupling?
 

On Mon, 01 May 2006 20:38:58 GMT, Lostgallifreyan
wrote:

"Phil Allison" wrote in
:

Audio band white noise is totally dominated by high frequency noise !!


White noise has equal amounts of all frequencies. We hear the HF dominate
because higher frequencies have more energy. (And because our ears are more
sensitive to it).

Ears are most sensitive around 1k, aren't they?

Tom

Is my LT44 transformer suitable for audio (de)coupling?
 

Tom MacIntyre wrote in
:

On Mon, 01 May 2006 20:38:58 GMT, Lostgallifreyan
wrote:

"Phil Allison" wrote in
:

Audio band white noise is totally dominated by high frequency noise
!!


White noise has equal amounts of all frequencies. We hear the HF
dominate because higher frequencies have more energy. (And because our
ears are more sensitive to it).

Ears are most sensitive around 1k, aren't they?

Tom


Probably. :) I wasn't thinking hard about that, I was just caught by the
claim that HF dominates white noise in the audio band, when white noise is
defined as being made up of all frequencies present with equal energy in
each.

Is my LT44 transformer suitable for audio (de)coupling?
 

On Mon, 01 May 2006 21:51:05 GMT, Lostgallifreyan
wrote:

Tom MacIntyre wrote in
:

On Mon, 01 May 2006 20:38:58 GMT, Lostgallifreyan
wrote:

"Phil Allison" wrote in
:

Audio band white noise is totally dominated by high frequency noise
!!


White noise has equal amounts of all frequencies. We hear the HF
dominate because higher frequencies have more energy. (And because our
ears are more sensitive to it).

Ears are most sensitive around 1k, aren't they?

Tom


Probably. :) I wasn't thinking hard about that, I was just caught by the
claim that HF dominates white noise in the audio band, when white noise is
defined as being made up of all frequencies present with equal energy in
each.

Hmmm...equal energy means that it would be more energy per octave at
higher frequencies, right?

Tom

Is my LT44 transformer suitable for audio (de)coupling?
 

Tom MacIntyre wrote in
:

On Mon, 01 May 2006 21:51:05 GMT, Lostgallifreyan
wrote:

Tom MacIntyre wrote in
m:

On Mon, 01 May 2006 20:38:58 GMT, Lostgallifreyan
wrote:

"Phil Allison" wrote in
:

Audio band white noise is totally dominated by high frequency
noise !!


White noise has equal amounts of all frequencies. We hear the HF
dominate because higher frequencies have more energy. (And because
our ears are more sensitive to it).

Ears are most sensitive around 1k, aren't they?

Tom


Probably. :) I wasn't thinking hard about that, I was just caught by
the claim that HF dominates white noise in the audio band, when white
noise is defined as being made up of all frequencies present with
equal energy in each.

Hmmm...equal energy means that it would be more energy per octave at
higher frequencies, right?

Tom


Yes, but that comes down to how you define the scale. The only reason,
following from that, to say that HF dominates in the audio band, is because
of expressing a log scale as lin, as pitch as opposed to frequency. If you
say that the pitch notation is purely based on musical needs, and prefer
the frequency scale for electronics analysis, surely you also have to
discard with it the notion of HF dominance.

The reason the claim that HF dominates seems wrong to me, is I think a
peice of string is its own length, regardless of whether we measue in
inches or centimetres, let alone a nonlinear scale. White noise has a very
specific definition, in which energy is equal across the spectrum, does not
dominate part of it. It's out perception of pitch that does that.

Is my LT44 transformer suitable for audio (de)coupling?
 

On Mon, 01 May 2006 22:46:14 GMT, Lostgallifreyan
wrote:

Tom MacIntyre wrote in
:

On Mon, 01 May 2006 21:51:05 GMT, Lostgallifreyan
wrote:

Tom MacIntyre wrote in
:

On Mon, 01 May 2006 20:38:58 GMT, Lostgallifreyan
wrote:

"Phil Allison" wrote in
:

Audio band white noise is totally dominated by high frequency
noise !!


White noise has equal amounts of all frequencies. We hear the HF
dominate because higher frequencies have more energy. (And because
our ears are more sensitive to it).

Ears are most sensitive around 1k, aren't they?

Tom


Probably. :) I wasn't thinking hard about that, I was just caught by
the claim that HF dominates white noise in the audio band, when white
noise is defined as being made up of all frequencies present with
equal energy in each.

Hmmm...equal energy means that it would be more energy per octave at
higher frequencies, right?

Tom


Yes, but that comes down to how you define the scale. The only reason,
following from that, to say that HF dominates in the audio band, is because
of expressing a log scale as lin, as pitch as opposed to frequency. If you
say that the pitch notation is purely based on musical needs, and prefer
the frequency scale for electronics analysis, surely you also have to
discard with it the notion of HF dominance.

The reason the claim that HF dominates seems wrong to me, is I think a
peice of string is its own length, regardless of whether we measue in
inches or centimetres, let alone a nonlinear scale. White noise has a very
specific definition, in which energy is equal across the spectrum, does not
dominate part of it. It's out perception of pitch that does that.


Interesting about the string, because we can simulate musical octaves
by folding a piece of string in half again and again.

Wouldn't a scale from, say, 100 Hz to 1600 Hz sound "interesting" if
we used 100 Hz as the semitone, rather than 2^(1/12) x f? :-)

Tom

Is my LT44 transformer suitable for audio (de)coupling?
 

Tom MacIntyre wrote in
:

On Mon, 01 May 2006 22:46:14 GMT, Lostgallifreyan
wrote:

Tom MacIntyre wrote in
m:

On Mon, 01 May 2006 21:51:05 GMT, Lostgallifreyan
wrote:

Tom MacIntyre wrote in
m:

On Mon, 01 May 2006 20:38:58 GMT, Lostgallifreyan
wrote:

"Phil Allison" wrote in
:

Audio band white noise is totally dominated by high frequency
noise !!


White noise has equal amounts of all frequencies. We hear the HF
dominate because higher frequencies have more energy. (And because
our ears are more sensitive to it).

Ears are most sensitive around 1k, aren't they?

Tom


Probably. :) I wasn't thinking hard about that, I was just caught by
the claim that HF dominates white noise in the audio band, when
white noise is defined as being made up of all frequencies present
with equal energy in each.

Hmmm...equal energy means that it would be more energy per octave at
higher frequencies, right?

Tom


Yes, but that comes down to how you define the scale. The only reason,
following from that, to say that HF dominates in the audio band, is
because of expressing a log scale as lin, as pitch as opposed to
frequency. If you say that the pitch notation is purely based on
musical needs, and prefer the frequency scale for electronics
analysis, surely you also have to discard with it the notion of HF
dominance.

The reason the claim that HF dominates seems wrong to me, is I think a
peice of string is its own length, regardless of whether we measue in
inches or centimetres, let alone a nonlinear scale. White noise has a
very specific definition, in which energy is equal across the
spectrum, does not dominate part of it. It's out perception of pitch
that does that.


Interesting about the string, because we can simulate musical octaves
by folding a piece of string in half again and again.

Wouldn't a scale from, say, 100 Hz to 1600 Hz sound "interesting" if
we used 100 Hz as the semitone, rather than 2^(1/12) x f? :-)

Tom


That would form the first 15 overtones of a natural harmonic series based
on a fundamental of 100 Hz, and yes, it does sound cool. :) If you've got a
synthesizer with either microtuning scales, or a resonant filter, you could
set that up.

Is my LT44 transformer suitable for audio (de)coupling?
 

"Lostgallifreyan" wrote in message
9.130...
"Phil Allison" wrote in
:

Audio band white noise is totally dominated by high frequency noise !!


White noise has equal amounts of all frequencies. We hear the HF dominate
because higher frequencies have more energy. (And because our ears are
more
sensitive to it).

Aren't all Gallifreyans bar The Doctor now lost, since the Dalek war
eradicated them ?

Arfa

Is my LT44 transformer suitable for audio (de)coupling?
 

"Arfa Daily" wrote in
:


"Lostgallifreyan" wrote in message
9.130...
"Phil Allison" wrote in
:

Audio band white noise is totally dominated by high frequency noise
!!


White noise has equal amounts of all frequencies. We hear the HF
dominate because higher frequencies have more energy. (And because
our ears are more
sensitive to it).

Aren't all Gallifreyans bar The Doctor now lost, since the Dalek war
eradicated them ?

Arfa




Precisely. :) You won't know which one I am. I have a lot of fun with this
name, I can tell you. Besides, time is Strange, too strange for Daleks.

Is my LT44 transformer suitable for audio (de)coupling?
 

Lostgallifreyan spake thus:

Tom MacIntyre wrote in
:

Wouldn't a scale from, say, 100 Hz to 1600 Hz sound "interesting" if
we used 100 Hz as the semitone, rather than 2^(1/12) x f? :-)

That would form the first 15 overtones of a natural harmonic series based
on a fundamental of 100 Hz, and yes, it does sound cool. :) If you've got a
synthesizer with either microtuning scales, or a resonant filter, you could
set that up.

Heck, took me about 3 minutes with Sound Forge. (Use the "Synthesis"
tool.) Interesting scale. Sounds like the intervals get flat going up,
to my ear. (Probably because it's untempered.)


--
Pierre, mon ami. Jetez encore un Scientologiste
dans le baquet d'acide.

- from a posting in alt.religion.scientology titled
"France recommends dissolving Scientologists"

Is my LT44 transformer suitable for audio (de)coupling?
 

"Lostgallifreyan"
"Phil Allison"

Audio band white noise is totally dominated by high frequency noise !!


White noise has equal amounts of all frequencies.


** Wrong.

It has equal amounts of noise energy in equal amounts of bandwidth.

So, 50% of the noise energy is in the band from 10 kHz to 20 kHz.

90 % is in the band from 2kHz to 20 kHz.

95 % is in the band from 1 kHz to 20 kHz.

99% is in the band from 200Hz to 20 kHz.

Get it ?



We hear the HF dominate
because higher frequencies have more energy.


** No - because it does utterly dominates the energy spectrum.


........ Phil

Is my LT44 transformer suitable for audio (de)coupling?
 

"GregS"

The noise voltage of many op-amps is almost flat from 1K to 100K, but
below 1 K
it moves upward. I'm looking at the LF353 as it has a very low level of
low frequency
noise, or at least the chart shows that. The AD711 has 18 nvHz at 1 kHz
but
60 nvHz at 1 Hz.


** What a complete ******.



........ Phil

Is my LT44 transformer suitable for audio (de)coupling?
 

"Lostgallifreyan"

Probably. :) I wasn't thinking hard about that, I was just caught by the
claim that HF dominates white noise in the audio band, when white noise is
defined as being made up of all frequencies present with equal energy in
each.


** WRONG.

Pink noise has equal energy in each octave band or fraction thereof.

However, white noise has about 30 dB more energy at the high end of the
audio band compared to the low end.




........ Phil

Is my LT44 transformer suitable for audio (de)coupling?
 

"Lostgallifreyan"

The reason the claim that HF dominates seems wrong to me, is I think a
peice of string is its own length, regardless of whether we measue in
inches or centimetres, let alone a nonlinear scale. White noise has a very
specific definition, in which energy is equal across the spectrum, does
not
dominate part of it. It's out perception of pitch that does that.



** Absolute CRAP.

Go away - half wit.



........... Phil

Is my LT44 transformer suitable for audio (de)coupling?
 

"Tom MacIntyre"

** Bandwidth in *electronics* is normally quoted in Hz, kHz, MHz, GHz etc.

Octaves are a musical notion, so not used much outside of audio and
acoustics.


An octave is a doubling of the frequency, so it has logarithmic
implications.



** Bandwidth in Hz etc directly indictates the *information* carrying
ability of a channel.

That is why it is used in electronics.




.......... Phil

Is my LT44 transformer suitable for audio (de)coupling?
 

"Phil Allison" wrote in
:


"Lostgallifreyan"

The reason the claim that HF dominates seems wrong to me, is I think
a peice of string is its own length, regardless of whether we measue
in inches or centimetres, let alone a nonlinear scale. White noise
has a very specific definition, in which energy is equal across the
spectrum, does not
dominate part of it. It's out perception of pitch that does that.



** Absolute CRAP.

Go away - half wit.



.......... Phil





Sledge away mate, you know it makes sense. :)

Remember this little gem:

[quote, you, earlier post]
It has equal amounts of noise energy in equal amounts of bandwidth.

So, 50% of the noise energy is in the band from 10 kHz to 20 kHz.

90 % is in the band from 2kHz to 20 kHz.

95 % is in the band from 1 kHz to 20 kHz.

99% is in the band from 200Hz to 20 kHz.
[/quote]

That looks like what I said, an equal spread across the frequency plot of
the spectrum. Pink noise, is as you said, the spread across the pitch plot.

If I took your line I could say that 99% was in the band up to 19.8 KHz
(1% from there to 20 KHz) and suggest that the LF was dominating. The
asymmetry comes from the change from plotting white noise as frequency, to
plotting as pitch.

Is my LT44 transformer suitable for audio (de)coupling?
 

"Lostgallifreyan"

** What an asinine ****ing idiot !

Must be one of them six toed "home studio" autistic mental retards.



The reason the claim that HF dominates seems wrong to me, is I think
a peice of string is its own length, regardless of whether we measue
in inches or centimetres, let alone a nonlinear scale. White noise
has a very specific definition, in which energy is equal across the
spectrum, does not
dominate part of it. It's out perception of pitch that does that.


** Absolute CRAP.

Go away - half wit.


Sledge away mate, you know it makes sense. :)


** I was far too kind before.

This evil cretin is a slimy public menace.




Remember this little gem:

[quote, you, earlier post]
It has equal amounts of noise energy in equal amounts of bandwidth.

So, 50% of the noise energy is in the band from 10 kHz to 20 kHz.

90 % is in the band from 2kHz to 20 kHz.

95 % is in the band from 1 kHz to 20 kHz.

99% is in the band from 200Hz to 20 kHz.
[/quote]

That looks like what I said, an equal spread across the frequency plot of
the spectrum.


** It is very clearly an unequal spread.

95% of the energy is above 1 kHz and only 5% below.


If I took your line I could say that 99% was in the band up to 19.8 KHz
(1% from there to 20 KHz) and suggest that the LF was dominating.


** But you would have to be a donkey ****ing, pointy headed moron to say
that.

Oh ....

but that is EXACTLY what you are .......






........ Phil

Is my LT44 transformer suitable for audio (de)coupling?
 

"Phil Allison" wrote in
:


"Lostgallifreyan"

** What an asinine ****ing idiot !

Must be one of them six toed "home studio" autistic mental retards.



The reason the claim that HF dominates seems wrong to me, is I
think a peice of string is its own length, regardless of whether we
measue in inches or centimetres, let alone a nonlinear scale. White
noise has a very specific definition, in which energy is equal
across the spectrum, does not
dominate part of it. It's out perception of pitch that does that.


** Absolute CRAP.

Go away - half wit.


Sledge away mate, you know it makes sense. :)


** I was far too kind before.

This evil cretin is a slimy public menace.




Remember this little gem:

[quote, you, earlier post]
It has equal amounts of noise energy in equal amounts of bandwidth.

So, 50% of the noise energy is in the band from 10 kHz to 20 kHz.

90 % is in the band from 2kHz to 20 kHz.

95 % is in the band from 1 kHz to 20 kHz.

99% is in the band from 200Hz to 20 kHz.
[/quote]

That looks like what I said, an equal spread across the frequency
plot of the spectrum.


** It is very clearly an unequal spread.

95% of the energy is above 1 kHz and only 5% below.


If I took your line I could say that 99% was in the band up to 19.8
KHz (1% from there to 20 KHz) and suggest that the LF was dominating.


** But you would have to be a donkey ****ing, pointy headed moron to
say that.

Oh ....

but that is EXACTLY what you are .......






....... Phil







Well, you give value for money, I'll give you that. :)

Is my LT44 transformer suitable for audio (de)coupling?
 

In article ,
Tom MacIntyre wrote:
** Bandwidth in *electronics* is normally quoted in Hz, kHz, MHz, GHz
etc.

Octaves are a musical notion, so not used much outside of audio and
acoustics.

An octave is a doubling of the frequency, so it has logarithmic
implications.

And much used in general electronics as in 6dB per octave filter, etc.
Even when not dealing with actual audio.

--
* I like you. You remind me of when I was young and stupid

Dave Plowman London SW
To e-mail, change noise into sound.

Is my LT44 transformer suitable for audio (de)coupling?
 

On 2006-05-01, Lostgallifreyan wrote:
Tom MacIntyre wrote in
:

Probably. :) I wasn't thinking hard about that, I was just caught by the
claim that HF dominates white noise in the audio band, when white noise is
defined as being made up of all frequencies present with equal energy in
each.

white noise is evenly distributed by frequency. (per Hz)

But frequency perception is logarythmic,
each octave has twice as many Hz from end to end as the one below it
therefore, with white noise, twice as much energy as the one below it.

Bye.
Jasen

Is my LT44 transformer suitable for audio (de)coupling?
 

Jasen Betts wrote in
:

On 2006-05-01, Lostgallifreyan wrote:
Tom MacIntyre wrote in
:

Probably. :) I wasn't thinking hard about that, I was just caught by
the claim that HF dominates white noise in the audio band, when white
noise is defined as being made up of all frequencies present with
equal energy in each.

white noise is evenly distributed by frequency. (per Hz)

But frequency perception is logarythmic,
each octave has twice as many Hz from end to end as the one below it
therefore, with white noise, twice as much energy as the one below it.

Bye.
Jasen


Don't tell me, tell those who disagreed with me. :)
You re-expressed exactly what I've been saying here.