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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#1
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Mono Stereo
Hi All,
There was a discussion on the FB self help forum for Peugeot 1007 owners recently... Someone said the standard radio fitted was mono Someone else said stereo,mono,stereo,mono.... After a while he clarified,?and said certainly the UK Models have CD Radios where the CD is stereo, but the tuner is mono. Is this common? Is it penny pinching? Does it give a better S/N ratio? ??? TIA Chris |
#2
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Mono Stereo
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#3
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Mono Stereo
Stereo fm is far worse s/n to Mono FM. Many DAB stations are in mono
whereas they are stereo on FM R4 extra and Smooth etc. I doubt anyone would fit a mono radio in a car these days, but there has for a long time been a progressive monoising circuit around that moves gradually to stereo as the signal level drops its supposed to be less annoying than the hiss from the stereo when itt is hanging on in bad areas. Its simply a mixer of the channels as the signal level drops below a set level. Some are frequency tailored as well. I think I'm right in saying the idea was invented by Phillips originally. However for DAB you need to ask Offcom not us. We will soon start this argument about restricting bit rates to cram more dross in at the expense of quality and the boiling mud mess you get on DAB over DAB plus. Brian -- ----- -- This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please Note this Signature is meaningless.! wrote in message ... Hi All, There was a discussion on the FB self help forum for Peugeot 1007 owners recently... Someone said the standard radio fitted was mono Someone else said stereo,mono,stereo,mono.... After a while he clarified,?and said certainly the UK Models have CD Radios where the CD is stereo, but the tuner is mono. Is this common? Is it penny pinching? Does it give a better S/N ratio? ??? TIA Chris |
#6
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Mono Stereo
On 17/04/2019 11:22, Max Demian wrote:
On 16/04/2019 23:24, wrote: Hi All, There was a discussion on the FB self help forum for Peugeot 1007 owners recently... Someone said the standard radio fitted was mono Someone else said stereo,mono,stereo,mono.... After a while he clarified,?and said certainly the UK Models have CD Radios where the CD is stereo, but the tuner is mono. Is this common? Is it penny pinching? Does it give a better S/N ratio? Stereo car radios usually use stereo/mono blend on FM so as reception worsens the stereo effect is reduced rather than getting hissy. In a poor reception area the stereo FM would /sound/ mono which might be the cause of the confusion. In a tin can like a Pug 1007, by the time you have got to 50mph you won't hear much detail from the radio anyway. |
#7
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Mono Stereo
On 16/04/2019 23:24, wrote:
Does it give a better S/N ratio? IIUC, for reasons of backward compatibility, a stereo FM transmission encodes stereo image into a pair of sum and difference signals[1]. So mono receivers can simply process the sum signal and get both channels combined into a single mono channel. A stereo receiver will need to add/subtract the difference signal from the main combined channel to get the separate L & R channels. The sum signal is transmitted using FM and the difference signal is amplitude modulated onto a sub carrier shifted up from the main carrier. (IIRC there is also a pilot tone included just above the baseband audio to signal the received that its a stereo transmission). Since the AM modulation will suffer more in poor reception conditions it can also introduce hiss. Many radios hence include a Stereo/Mono switch to elect for mono with no hiss. Some of the posher car radios actually use a mixer for the stereo decoding, so they can switch the stereo in and out in gradual way depending on how much noise is being detected. [1] Conceptually not unlike the way colour was added to mono TV -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#8
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Mono Stereo
On 17/04/2019 13:33, John Rumm wrote:
On 16/04/2019 23:24, wrote: Does it give a better S/N ratio? IIUC, for reasons of backward compatibility, a stereo FM transmission encodes stereo image into a pair of sum and difference signals[1]. So mono receivers can simply process the sum signal and get both channels combined into a single mono channel. A stereo receiver will need to add/subtract the difference signal from the main combined channel to get the separate L & R channels. The sum signal is transmitted using FM and the difference signal is amplitude modulated onto a sub carrier shifted up from the main carrier. (IIRC there is also a pilot tone included just above the baseband audio to signal the received that its a stereo transmission). Since the AM modulation will suffer more in poor reception conditions it can also introduce hiss. Many radios hence include a Stereo/Mono switch to elect for mono with no hiss. Some of the posher car radios actually use a mixer for the stereo decoding, so they can switch the stereo in and out in gradual way depending on how much noise is being detected. [1] Conceptually not unlike the way colour was added to mono TV Not quite correct. https://en.wikipedia.org/wiki/FM_broadcasting#Stereo_FM is definitive. the reason for worsening S/N is quite simply that more bandwidth is needed to get stereo and that simply lets in more noise. AM or FM doesn't really make much odds here. -- "Strange as it seems, no amount of learning can cure stupidity, and higher education positively fortifies it." - Stephen Vizinczey |
#9
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Mono Stereo
On 17/04/2019 13:44, The Natural Philosopher wrote:
On 17/04/2019 13:33, John Rumm wrote: On 16/04/2019 23:24, wrote: Does it give a better S/N ratio? IIUC, for reasons of backward compatibility, a stereo FM transmission encodes stereo image into a pair of sum and difference signals[1]. So mono receivers can simply process the sum signal and get both channels combined into a single mono channel. A stereo receiver will need to add/subtract the difference signal from the main combined channel to get the separate L & R channels. The sum signal is transmitted using FM and the difference signal is amplitude modulated onto a sub carrier shifted up from the main carrier. (IIRC there is also a pilot tone included just above the baseband audio to signal the received that its a stereo transmission). Since the AM modulation will suffer more in poor reception conditions it can also introduce hiss. Many radios hence include a Stereo/Mono switch to elect for mono with no hiss. Some of the posher car radios actually use a mixer for the stereo decoding, so they can switch the stereo in and out in gradual way depending on how much noise is being detected. [1] Conceptually not unlike the way colour was added to mono TV Not quite correct. https://en.wikipedia.org/wiki/FM_broadcasting#Stereo_FM is definitive. ...and actually appears to be a fairly close match to my overview above. the reason for worsening S/N is quite simply that more bandwidth is needed to get stereo and that simply lets in more noise. From your source... "The (L+R) Main channel signal is transmitted as baseband audio limited to the range of 30 Hz to 15 kHz. The (LR) signal is amplitude modulated onto a 38 kHz double-sideband suppressed-carrier (DSB-SC) signal occupying the baseband range of 23 to 53 kHz." later: "for a given RF level at the receiver, the signal-to-noise ratio and multipath distortion for the stereo signal will be worse than for the mono receiver." AM or FM doesn't really make much odds here. Its the AM modulated difference signal (i.e. the bit that carries the stereo information) that suffers the poorer SNR. Whether one argues that is because or its modulation technique or its the lower bandwidth is a bit moot (I would say both are a factor, but AM is still the better choice for narrowband applications). However I will concede a better wording may have been "Since its the AM modulated part of the signal that will suffer more in poor reception conditions..." -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#10
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Mono Stereo
On 17/04/2019 14:53, John Rumm wrote:
On 17/04/2019 13:44, The Natural Philosopher wrote: On 17/04/2019 13:33, John Rumm wrote: On 16/04/2019 23:24, wrote: Does it give a better S/N ratio? IIUC, for reasons of backward compatibility, a stereo FM transmission encodes stereo image into a pair of sum and difference signals[1]. So mono receivers can simply process the sum signal and get both channels combined into a single mono channel. A stereo receiver will need to add/subtract the difference signal from the main combined channel to get the separate L & R channels. The sum signal is transmitted using FM and the difference signal is amplitude modulated onto a sub carrier shifted up from the main carrier. (IIRC there is also a pilot tone included just above the baseband audio to signal the received that its a stereo transmission). Since the AM modulation will suffer more in poor reception conditions it can also introduce hiss. Many radios hence include a Stereo/Mono switch to elect for mono with no hiss. Some of the posher car radios actually use a mixer for the stereo decoding, so they can switch the stereo in and out in gradual way depending on how much noise is being detected. [1] Conceptually not unlike the way colour was added to mono TV Not quite correct. https://en.wikipedia.org/wiki/FM_broadcasting#Stereo_FM is definitive. ..and actually appears to be a fairly close match to my overview above. the reason for worsening S/N is quite simply that more bandwidth is needed to get stereo and that simply lets in more noise. From your source... "The (L+R) Main channel signal is transmitted as baseband audio limited to the range of 30 Hz to 15 kHz. The (LR) signal is amplitude modulated onto a 38 kHz double-sideband suppressed-carrier (DSB-SC) signal occupying the baseband range of 23 to 53 kHz." later: "for a given RF level at the receiver, the signal-to-noise ratio and multipath distortion for the stereo signal will be worse than for the mono receiver." AM or FM doesn't really make much odds here. Its the AM modulated difference signal (i.e. the bit that carries the stereo information) that suffers the poorer SNR. Whether one argues that is because or its modulation technique or its the lower bandwidth is a bit moot (I would say both are a factor, but AM is still the better choice for narrowband applications). However I will concede a better wording may have been "Since its the AM modulated part of the signal that will suffer more in poor reception conditions..." No, that still doesn't wash. Its the 38kHhz subcarrier part that suffers worse. The FM S/N is only better because it occupies a humongous bandwidth - 400kHz - channel. Narrow band FM is just as noisy as AM The stereo subcarrier is only 38khz wide. https://en.wikipedia.org/wiki/Shanno...artley_theorem is what yopu need toi understand. AM is restricted to eseentially a channel as wide as the audio bandwidth being transmitted. FM may *or may not* use a wider channel, That's why it's possible to get lower S/N. The key thing is that its lower bandwidth. -- A lie can travel halfway around the world while the truth is putting on its shoes. |
#11
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Mono Stereo
Thanks Brian,
but I think DAB (Digital And Bad??) Was just a twinkle when these cars and their factory fit radios were on the drawing board. Cheers Chris |
#12
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Mono Stereo
In article ,
wrote: After a while he clarified,?and said certainly the UK Models have CD Radios where the CD is stereo, but the tuner is mono. I'd be surprised if they'd bother. Is this common? Is it penny pinching? Does it give a better S/N ratio? Car FM radios usually have a special stereo decoder. It notches out any interference pulses from the audio, and does a gradual blend from stereo to mono, depending of signal strength. Without that, FM reception would sound pretty nasty in all but the highest signal strength areas. -- *Make it idiot-proof and someone will make a better idiot. Dave Plowman London SW To e-mail, change noise into sound. |
#13
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Mono Stereo
In article ,
Brian Gaff wrote: However for DAB you need to ask Offcom not us. We will soon start this argument about restricting bit rates to cram more dross in at the expense of quality and the boiling mud mess you get on DAB over DAB plus. Think it costs the broadcaster more, the higher bitrate. I have DAB in the old car - with a very posh and expensive aerial. Never ever heard boiling mud on that anywhere in the country. But it will change to FM if it loses the DAB signal totally. -- *A closed mouth gathers no feet.* Dave Plowman London SW To e-mail, change noise into sound. |
#14
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Mono Stereo
wrote:
Thanks Brian, but I think DAB (Digital And Bad??) Was just a twinkle when these cars and their factory fit radios were on the drawing board. Cheers Chris DAB in the UK , testing from 1990 public rollout from 1995. Peugot 1007 introduced 2005. GH |
#15
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Mono Stereo
In article , Dave Plowman (News)
scribeth thus In article , Brian Gaff wrote: However for DAB you need to ask Offcom not us. We will soon start this argument about restricting bit rates to cram more dross in at the expense of quality and the boiling mud mess you get on DAB over DAB plus. Think it costs the broadcaster more, the higher bitrate. Yep sure does, for a local sort of station DAB at say 32 odd K/bits around £40 K "ish" 128 around £70K and 192K forget it;(.. I have DAB in the old car - with a very posh and expensive aerial. Never ever heard boiling mud on that anywhere in the country. But it will change to FM if it loses the DAB signal totally. -- Tony Sayer Man is least himself when he talks in his own person. Give him a keyboard, and he will reveal himself. |
#16
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Mono Stereo
In article , The Natural Philosopher
scribeth thus On 17/04/2019 14:53, John Rumm wrote: On 17/04/2019 13:44, The Natural Philosopher wrote: On 17/04/2019 13:33, John Rumm wrote: On 16/04/2019 23:24, wrote: Does it give a better S/N ratio? IIUC, for reasons of backward compatibility, a stereo FM transmission encodes stereo image into a pair of sum and difference signals[1]. So mono receivers can simply process the sum signal and get both channels combined into a single mono channel. A stereo receiver will need to add/subtract the difference signal from the main combined channel to get the separate L & R channels. The sum signal is transmitted using FM and the difference signal is amplitude modulated onto a sub carrier shifted up from the main carrier. (IIRC there is also a pilot tone included just above the baseband audio to signal the received that its a stereo transmission). Since the AM modulation will suffer more in poor reception conditions it can also introduce hiss. Many radios hence include a Stereo/Mono switch to elect for mono with no hiss. Some of the posher car radios actually use a mixer for the stereo decoding, so they can switch the stereo in and out in gradual way depending on how much noise is being detected. [1] Conceptually not unlike the way colour was added to mono TV Not quite correct. https://en.wikipedia.org/wiki/FM_broadcasting#Stereo_FM is definitive. ..and actually appears to be a fairly close match to my overview above. the reason for worsening S/N is quite simply that more bandwidth is needed to get stereo and that simply lets in more noise. From your source... "The (L+R) Main channel signal is transmitted as baseband audio limited to the range of 30 Hz to 15 kHz. The (L0 onto a 38 kHz double-sideband suppressed-carrier (DSB-SC) signal occupying the baseband range of 23 to 53 kHz." later: "for a given RF level at the receiver, the signal-to-noise ratio and multipath distortion for the stereo signal will be worse than for the mono receiver." AM or FM doesn't really make much odds here. Its the AM modulated difference signal (i.e. the bit that carries the stereo information) that suffers the poorer SNR. Whether one argues that is because or its modulation technique or its the lower bandwidth is a bit moot (I would say both are a factor, but AM is still the better choice for narrowband applications). However I will concede a better wording may have been "Since its the AM modulated part of the signal that will suffer more in poor reception conditions..." No, that still doesn't wash. Its the 38kHhz subcarrier part that suffers worse. The FM S/N is only better because it occupies a humongous bandwidth - 400kHz - channel. Narrow band FM is just as noisy as AM The stereo subcarrier is only 38khz wide. https://en.wikipedia.org/wiki/Shanno...artley_theorem is what yopu need toi understand. AM is restricted to eseentially a channel as wide as the audio bandwidth being transmitted. FM may *or may not* use a wider channel, That's why it's possible to get lower S/N. The key thing is that its lower bandwidth. FWIW i had a new type of specialist FM receiver on demo/evaluation recently its a BW Broadcast encore series rebroadcast receiver which apart from being very good at what it does has lots of other needed bells and whistles like diversity reception, two tuner and multipath cancellation the capability to receive distant stations whilst ones on the same mast where it is may be knocking out kilowatts on close by channels on FM, DAB or TV etc. However its main purpose is to pick up a distant transmitter and provide a high quality signal for local rebroadcast transmission. Now its getting quite fashionable to use digital signal processing in such devices, they do now regenerate the 19K stereo pilot tone, regen the RDS etc but i had this one and put it on, you do have the Read the bloody manual to get it to do what you want it to do, but i had it tuned to a very good quality FM transmission pair of phones plugged in and just a few inches of wire plugged in the back as a makeshift aerial. Went and had tea and came back, phones on very impressive audio, sounded very close to CD very quiet background all fine. Further investigation revealed that what they call FMSI was enabled this is where the incoming difference signal is sampled out of band and a few other interesting things happen to it. Now they do have a measurement mode where you can listen to the original signal to check that under "as is" conditions when that was enabled the Almost CD quality disappeared in a very mushy hiss! Hooking it up to a better aerial alleviated that but it was very interesting to see or hear rather just how good the signal processing was you can select conventional stereo "blend", well a slightly more advanced version etc, but switching the signal processing in the difference was remarkable even back on the bit of wire aerial. At the prices these are its not intended as a domestic product and is a PITA to tune in different channels etc but just shows what can be done in the receiver to improve a deficiency of the original GE Zenith pilot tone system!.. https://www.bwbroadcast.com/bwbroadc...ore/64/product -- Tony Sayer Man is least himself when he talks in his own person. Give him a keyboard, and he will reveal himself. |
#17
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Mono Stereo
In article ,
Jethro_uk wrote: I have DAB in the old car - with a very posh and expensive aerial. Never ever heard boiling mud on that anywhere in the country. But it will change to FM if it loses the DAB signal totally. Last two cars came with DAB (whether you wanted it or not). Every motorway journey I did (Birmingham to Stoke, Eastleigh, Gloucester or Bournemouth, depending on the meeting) it cut out and "went funny". While FM was rock solid, as was the USB port for memory stick Of course it's going to depend on where you are in the country. Same as any reception. City centres with tall buildings - or hilly country tend to show up the shortcomings of FM. And DAB was designed for mobile reception. -- *Speak softly and carry a cellular phone * Dave Plowman London SW To e-mail, change noise into sound. |
#18
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Mono Stereo
In article ,
Jethro_uk wrote: Of course it's going to depend on where you are in the country. Same as any reception. City centres with tall buildings - or hilly country tend to show up the shortcomings of FM. And DAB was designed for mobile reception. Which is why I was careful to state it was *driving* that I experienced **** performance. Driving across the vast mountain ranges of Worcestershire, Gloucestershire, Wiltshire, Hampshire and Dorset. All terrain that FM was crystal clear over. Except for a dead spot near M5J5 which I think was due to the sodding great transmitter there. It's obviously going to depend on which transmitters are where. It's not a public service where the whole country gets fair do's. Anymore than with anything else. So rather obviously centres of population are better covered. The real test is to do a comparison where signal strengths and expected coverage are about the same. One thing I did discover, though. An aerial designed for FM doesn't work well with DAB. And even maker's systems factory installed ain't necessarily state of the art. I have one car with a factory FM radio. Aerial in the screen. Noticeably poorer FM reception than the old car on FM with a roof aerial. -- *How many roads must a man travel down before he admits he is lost? * Dave Plowman London SW To e-mail, change noise into sound. |
#19
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Mono Stereo
On Wed, 17 Apr 2019 12:27:30 +0100, Andrew wrote:
On 17/04/2019 11:22, Max Demian wrote: On 16/04/2019 23:24, wrote: Hi All, There was a discussion on the FB self help forum for Peugeot 1007 owners recently... Someone said the standard radio fitted was mono Someone else said stereo,mono,stereo,mono.... After a while he clarified,?and said certainly the UK Models have CD Radios where the CD is stereo, but the tuner is mono. Is this common? Is it penny pinching? Does it give a better S/N ratio? Stereo car radios usually use stereo/mono blend on FM so as reception worsens the stereo effect is reduced rather than getting hissy. In a poor reception area the stereo FM would /sound/ mono which might be the cause of the confusion. In a tin can like a Pug 1007, by the time you have got to 50mph you won't hear much detail from the radio anyway. A match made in heaven as far as low bit rate DAB is concerned. DAB is basically a low quality broadcasting system designed to match the equally low quality listening environments it was optimised for. The egregious aspect of DAB was in its marketing claims that it could replace the old and tried FM broadcasting system in all usage cases. Clearly, once the bean counters had taken advantage of the cost cutting low bandwidth options inherent to the system, this rapidly (and with obscene haste) became yet another "Lie by omission advertising claim" (which is at the heart of pretty well all commercial advertising - "The large print giveth, whilst the small print taketh away." principle). -- Johnny B Good |
#20
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Mono Stereo
In article ,
Johnny B Good wrote: A match made in heaven as far as low bit rate DAB is concerned. DAB is basically a low quality broadcasting system designed to match the equally low quality listening environments it was optimised for. No it is not. But like many digital systems, it's easy to alter the bitrate. Which costs the broadcaster less in rental. That is a facility DAB offers. Up to the broadcaster and the listener if they would prefer to pay more for better quality. But then FM reception in a car or portable is rarely perfect either. Multipath introduces distortion. -- *Lottery: A tax on people who are bad at math. Dave Plowman London SW To e-mail, change noise into sound. |
#21
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Mono Stereo
In article ,
Jethro_uk wrote: On Thu, 18 Apr 2019 12:59:33 +0000, Johnny B Good wrote: The egregious aspect of DAB was in its marketing claims that it could replace the old and tried FM broadcasting system in all usage cases. Utter ********, of course. Particularly for battery powered tranny radios. Dunno about you, but I find FM reception on a portable radio less than perfect in this part of London. Same as it always has been. -- *Does fuzzy logic tickle? * Dave Plowman London SW To e-mail, change noise into sound. |
#22
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Mono Stereo
On Wed, 17 Apr 2019 14:53:23 +0100, John Rumm wrote:
On 17/04/2019 13:44, The Natural Philosopher wrote: On 17/04/2019 13:33, John Rumm wrote: On 16/04/2019 23:24, wrote: Does it give a better S/N ratio? IIUC, for reasons of backward compatibility, a stereo FM transmission encodes stereo image into a pair of sum and difference signals[1]. So mono receivers can simply process the sum signal and get both channels combined into a single mono channel. A stereo receiver will need to add/subtract the difference signal from the main combined channel to get the separate L & R channels. The sum signal is transmitted using FM and the difference signal is amplitude modulated onto a sub carrier shifted up from the main carrier. (IIRC there is also a pilot tone included just above the baseband audio to signal the received that its a stereo transmission). Since the AM modulation will suffer more in poor reception conditions it can also introduce hiss. Many radios hence include a Stereo/Mono switch to elect for mono with no hiss. Some of the posher car radios actually use a mixer for the stereo decoding, so they can switch the stereo in and out in gradual way depending on how much noise is being detected. [1] Conceptually not unlike the way colour was added to mono TV Not quite correct. https://en.wikipedia.org/wiki/FM_broadcasting#Stereo_FM is definitive. ..and actually appears to be a fairly close match to my overview above. the reason for worsening S/N is quite simply that more bandwidth is needed to get stereo and that simply lets in more noise. From your source... "The (L+R) Main channel signal is transmitted as baseband audio limited to the range of 30 Hz to 15 kHz. The (LR) signal is amplitude modulated onto a 38 kHz double-sideband suppressed-carrier (DSB-SC) signal occupying the baseband range of 23 to 53 kHz." later: "for a given RF level at the receiver, the signal-to-noise ratio and multipath distortion for the stereo signal will be worse than for the mono receiver." AM or FM doesn't really make much odds here. Its the AM modulated difference signal (i.e. the bit that carries the stereo information) that suffers the poorer SNR. Whether one argues that is because or its modulation technique or its the lower bandwidth is a bit moot (I would say both are a factor, but AM is still the better choice for narrowband applications). However I will concede a better wording may have been "Since its the AM modulated part of the signal that will suffer more in poor reception conditions..." To make it clear, this "AM modulation" is only referenced to the baseband audio signals that are frequency modulating the VHF carrier. Since it's (afaicr) some 20dB down on the primary baseband modulation, this stereo difference signal adds extra noise (an extra 3 or 6dB overall under ideal conditions afaicr). Under less ideal conditions, it adds even more noise. Since it manifests itself as "hiss", a simple hf blending of the left and right channels can mitigate this noise at the expense of stereo separation. A receiver design which applies a graduated increase in reducing the effective stereo separation at the higher audio frequencies provides a more graceful degradation to pure mono with worsening reception conditions beyond a lower threshold limit of acceptability for full stereo separation operation. -- Johnny B Good |
#23
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Mono Stereo
On Wednesday, 17 April 2019 09:43:45 UTC+1, Brian Gaff wrote:
Stereo fm is far worse s/n to Mono FM. Many DAB stations are in mono whereas they are stereo on FM R4 extra and Smooth etc. I think that DAB has three 'grades': mono, 'joint stereo' and 'full stereo'. AFAIK only radio 3 is in full stereo (at least some of the time). In my expereice FM stereo is a only slightly more noisy than FM mono, provided the signal strength is good. Robert |
#24
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#25
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On 18/04/2019 10:58, Jethro_uk wrote:
On Wed, 17 Apr 2019 15:32:41 +0100, Dave Plowman (News) wrote: In article , Brian Gaff wrote: However for DAB you need to ask Offcom not us. We will soon start this argument about restricting bit rates to cram more dross in at the expense of quality and the boiling mud mess you get on DAB over DAB plus. Think it costs the broadcaster more, the higher bitrate. I have DAB in the old car - with a very posh and expensive aerial. Never ever heard boiling mud on that anywhere in the country. But it will change to FM if it loses the DAB signal totally. Last two cars came with DAB (whether you wanted it or not). Every motorway journey I did (Birmingham to Stoke, Eastleigh, Gloucester or Bournemouth, depending on the meeting) it cut out and "went funny". While FM was rock solid, as was the USB port for memory stick 1. Inadequate DAB aerial. Was it using the same aerial as the FM, or a windscreen thing, or whatever? 2. Insensitive tuner, or one that couldn't discriminate against strong adjacent muxes. Bill |
#26
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Mono Stereo
On Tuesday, 16 April 2019 23:24:16 UTC+1, wrote:
Hi All, There was a discussion on the FB self help forum for Peugeot 1007 owners recently... Someone said the standard radio fitted was mono Someone else said stereo,mono,stereo,mono.... After a while he clarified,?and said certainly the UK Models have CD Radios where the CD is stereo, but the tuner is mono. Is this common? Is it penny pinching? Does it give a better S/N ratio? ??? TIA Fiddle with the controls. If it has a balance control, it is stereo. |
#27
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Mono Stereo
On 17/04/2019 13:33, John Rumm wrote:
On 16/04/2019 23:24, wrote: Does it give a better S/N ratio? The sum signal is transmitted using FM and the difference signal is amplitude modulated onto a sub carrier shifted up from the main carrier. (IIRC there is also a pilot tone included just above the baseband audio to signal the received that its a stereo transmission). Since the AM modulation will suffer more in poor reception conditions it can also introduce hiss. The noise is as a result of FM's 'triangular noise spectrum'. The stereo difference signals (which are between 23 and 53kHz are far more impacted by noise than the mono channel 0 to 15 kHz. The 'extra' noise as a result of the difference channel is actually anti-phase L/R, you can remove it by simply summing L and R channels together, rather than disabling the stereo decoder within the tuner . The SCA system that the US used as an additional independent audio channel around 67 kHz was servery impacted, and required a very strong signal to remain noise free. https://en.wikipedia.org/wiki/FM_broadcasting#/media/File:RDS_vs_DirectBand_FM-spectrum2.svg -- Mark Please replace invalid and invalid with gmx and net to reply. |
#28
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Mono Stereo
In article , Dave Plowman (News)
scribeth thus In article , Jethro_uk wrote: Of course it's going to depend on where you are in the country. Same as any reception. City centres with tall buildings - or hilly country tend to show up the shortcomings of FM. And DAB was designed for mobile reception. Which is why I was careful to state it was *driving* that I experienced **** performance. Driving across the vast mountain ranges of Worcestershire, Gloucestershire, Wiltshire, Hampshire and Dorset. All terrain that FM was crystal clear over. Except for a dead spot near M5J5 which I think was due to the sodding great transmitter there. It's obviously going to depend on which transmitters are where. It's not a public service where the whole country gets fair do's. Anymore than with anything else. So rather obviously centres of population are better covered. The real test is to do a comparison where signal strengths and expected coverage are about the same. One thing I did discover, though. An aerial designed for FM doesn't work well with DAB. And even maker's systems factory installed ain't necessarily state of the art. I have one car with a factory FM radio. Aerial in the screen. Noticeably poorer FM reception than the old car on FM with a roof aerial. Those on screen things are ****e squared we had Taxi drivers trying to use them for their Two-way radios and they were around a tenth as efficient as a roof mounted one either a mag base or hole in the roof mount... -- Tony Sayer Man is least himself when he talks in his own person. Give him a keyboard, and he will reveal himself. |
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Mono Stereo
In article , Bill Wright
scribeth thus On 18/04/2019 10:58, Jethro_uk wrote: On Wed, 17 Apr 2019 15:32:41 +0100, Dave Plowman (News) wrote: In article , Brian Gaff wrote: However for DAB you need to ask Offcom not us. We will soon start this argument about restricting bit rates to cram more dross in at the expense of quality and the boiling mud mess you get on DAB over DAB plus. Think it costs the broadcaster more, the higher bitrate. I have DAB in the old car - with a very posh and expensive aerial. Never ever heard boiling mud on that anywhere in the country. But it will change to FM if it loses the DAB signal totally. Last two cars came with DAB (whether you wanted it or not). Every motorway journey I did (Birmingham to Stoke, Eastleigh, Gloucester or Bournemouth, depending on the meeting) it cut out and "went funny". While FM was rock solid, as was the USB port for memory stick 1. Inadequate DAB aerial. Was it using the same aerial as the FM, or a windscreen thing, or whatever? 2. Insensitive tuner, or one that couldn't discriminate against strong adjacent muxes. Bill That's more the problem, seems most all DAB radios the front end is wide open no tuned RF stages at all... -- Tony Sayer Man is least himself when he talks in his own person. Give him a keyboard, and he will reveal himself. |
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Mono Stereo
In article ,
Bill Wright wrote: 1. Inadequate DAB aerial. Was it using the same aerial as the FM, or a windscreen thing, or whatever? Yup. My only DAB car unit is an aftermarket Blaupunkt in the old Rover. Top of the range Blaupunkt - at the time. Since I don't change that car every couple of years wanted something good. The DAB aerial input was separate to the FM/AM one. It came with a stick on windscreen DAB aerial. Pretty useless - as well as looking horrid. FM/AM using the original wing mounted telescopic aerial just fine. It may well have been on here I got the heads up about a local (Wandsworth) aerial supplier that do all sorts of specialist aerials for mobile reception. And they had a roof one with twin amplifiers - one for DAB, one for the rest, and twin feeders. Cost more than many a car radio new. But works a treat. Cost even more to have a new nearside front wing fitted to get rid of the original aerial hole. ;-) But it's no different from the best TV or posh FM tuner. Neither will work well without a decent aerial. -- *Procrastination is the art of keeping up with yesterday. Dave Plowman London SW To e-mail, change noise into sound. |
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Mono Stereo
On 18/04/2019 10:56, Jethro_uk wrote:
On Wed, 17 Apr 2019 18:43:41 +0000, Marland wrote: wrote: Thanks Brian, but I think DAB (Digital And Bad??) Was just a twinkle when these cars and their factory fit radios were on the drawing board. Cheers Chris DAB in the UK , testing from 1990 public rollout from 1995. So I've spent 24 years avoiding it It's sounds so ****ing awful. The Archers on R4 DAB sounds lifeless and flat yet on FM (even if a bit poppy and noisy) has depth and life. And is in stereo. 2 cars with DAB and coverage about Scotland is dire. 1 DAB/FM radio in the kitchen (spends it's life on R4 FM) and I'm optical line of site to the most power DAB transmitter in Scotland and the DAB reception is ****e. The proponents still pushing DAB now need to be castrated in public for forcing this bag of dated pish onto the public. (I feel much better for that.) |
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Mono Stereo
On 19/04/2019 13:13, Dave Plowman (News) wrote:
But it's no different from the best TV or posh FM tuner. Neither will work well without a decent aerial. DAB doesn't work well even with a good antenna. It's a **** poor standard designed for 1995 level electronics with no upgrade potential. Having had it foisted on us, nobody in power is prepared to admit it's crap and should be ditched. It offers no improved quality of reception over FM. My 1969 Roberts R707 FM portable radio sounds better than just about all modern portable radios, FM or DAB. |
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Mono Stereo
In article , mm0fmf wrote:
On 19/04/2019 13:13, Dave Plowman (News) wrote: But it's no different from the best TV or posh FM tuner. Neither will work well without a decent aerial. DAB doesn't work well even with a good antenna. It's a **** poor standard designed for 1995 level electronics with no upgrade potential. Having had it foisted on us, nobody in power is prepared to admit it's crap and should be ditched. It offers no improved quality of reception over FM. My 1969 Roberts R707 FM portable radio sounds better than just about all modern portable radios, FM or DAB. It offers signifiacant immprovement for the motorist in heavily built up areas. -- from KT24 in Surrey, England "I'd rather die of exhaustion than die of boredom" Thomas Carlyle |
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Mono Stereo
In article ,
mm0fmf wrote: On 19/04/2019 13:13, Dave Plowman (News) wrote: But it's no different from the best TV or posh FM tuner. Neither will work well without a decent aerial. DAB doesn't work well even with a good antenna. You've not read my previous posts? It's a **** poor standard designed for 1995 level electronics with no upgrade potential. It has an excellent downgrade potential which the broadcasters grabbed to save money. In the same way as with digital TV. Having had it foisted on us, nobody in power is prepared to admit it's crap and should be ditched. It offers no improved quality of reception over FM. You've not read my previous posts? My 1969 Roberts R707 FM portable radio sounds better than just about all modern portable radios, FM or DAB. If a portable radio is how you judge sound quality, it says rather a lot. -- *If you don't like the news, go out and make some. Dave Plowman London SW To e-mail, change noise into sound. |
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Mono Stereo
In article , mm0fmf
scribeth thus On 19/04/2019 13:13, Dave Plowman (News) wrote: But it's no different from the best TV or posh FM tuner. Neither will work well without a decent aerial. DAB doesn't work well even with a good antenna. It's a **** poor standard designed for 1995 level electronics with no upgrade potential. Having had it foisted on us, nobody in power is prepared to admit it's crap and should be ditched. It offers no improved quality of reception over FM. My 1969 Roberts R707 FM portable radio sounds better than just about all modern portable radios, FM or DAB. Your not that bloke; "DAB sounds worse than FM" are you;?... -- Tony Sayer Man is least himself when he talks in his own person. Give him a keyboard, and he will reveal himself. |
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Mono Stereo
On 21/04/2019 22:42, tony sayer wrote:
In article , mm0fmf scribeth thus On 19/04/2019 13:13, Dave Plowman (News) wrote: But it's no different from the best TV or posh FM tuner. Neither will work well without a decent aerial. DAB doesn't work well even with a good antenna. It's a **** poor standard designed for 1995 level electronics with no upgrade potential. Having had it foisted on us, nobody in power is prepared to admit it's crap and should be ditched. It offers no improved quality of reception over FM. My 1969 Roberts R707 FM portable radio sounds better than just about all modern portable radios, FM or DAB. Your not that bloke; "DAB sounds worse than FM" are you;?... No. But DAB does sound ****e. Problem being having some expensive audio gear at home gets you used to stuff sounding good. The last car's original owner had fitted a £1200 audio upgrade which sounded fabulous on my high rate MP3s and CDs but the DAB was dire. FM sounded fine. |
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Mono Stereo
"mm0fmf" wrote in message ... On 21/04/2019 22:42, tony sayer wrote: In article , mm0fmf scribeth thus On 19/04/2019 13:13, Dave Plowman (News) wrote: But it's no different from the best TV or posh FM tuner. Neither will work well without a decent aerial. DAB doesn't work well even with a good antenna. It's a **** poor standard designed for 1995 level electronics with no upgrade potential. Having had it foisted on us, nobody in power is prepared to admit it's crap and should be ditched. It offers no improved quality of reception over FM. My 1969 Roberts R707 FM portable radio sounds better than just about all modern portable radios, FM or DAB. Your not that bloke; "DAB sounds worse than FM" are you;?... No. But DAB does sound ****e. Problem being having some expensive audio gear at home gets you used to stuff sounding good. The last car's original owner had fitted a £1200 audio upgrade which sounded fabulous on my high rate MP3s and CDs but the DAB was dire. FM sounded fine. if you love radio don't buy dab ..........as the advert doesn't go .... |
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Mono Stereo
On 17/04/2019 14:53, John Rumm wrote:
On 17/04/2019 13:44, The Natural Philosopher wrote: On 17/04/2019 13:33, John Rumm wrote: On 16/04/2019 23:24, wrote: Does it give a better S/N ratio? IIUC, for reasons of backward compatibility, a stereo FM transmission encodes stereo image into a pair of sum and difference signals[1]. So mono receivers can simply process the sum signal and get both channels combined into a single mono channel. A stereo receiver will need to add/subtract the difference signal from the main combined channel to get the separate L & R channels. The sum signal is transmitted using FM and the difference signal is amplitude modulated onto a sub carrier shifted up from the main carrier. (IIRC there is also a pilot tone included just above the baseband audio to signal the received that its a stereo transmission). Since the AM modulation will suffer more in poor reception conditions it can also introduce hiss. Many radios hence include a Stereo/Mono switch to elect for mono with no hiss. Some of the posher car radios actually use a mixer for the stereo decoding, so they can switch the stereo in and out in gradual way depending on how much noise is being detected. [1] Conceptually not unlike the way colour was added to mono TV Not quite correct. https://en.wikipedia.org/wiki/FM_broadcasting#Stereo_FM is definitive. ..and actually appears to be a fairly close match to my overview above. the reason for worsening S/N is quite simply that more bandwidth is needed to get stereo and that simply lets in more noise. From your source... "The (L+R) Main channel signal is transmitted as baseband audio limited to the range of 30 Hz to 15 kHz. The (LR) signal is amplitude modulated onto a 38 kHz double-sideband suppressed-carrier (DSB-SC) signal occupying the baseband range of 23 to 53 kHz." later: "for a given RF level at the receiver, the signal-to-noise ratio and multipath distortion for the stereo signal will be worse than for the mono receiver." AM or FM doesn't really make much odds here. Its the AM modulated difference signal (i.e. the bit that carries the stereo information) that suffers the poorer SNR. Whether one argues that is because or its modulation technique or its the lower bandwidth is a bit moot (I would say both are a factor, but AM is still the better choice for narrowband applications). However I will concede a better wording may have been "Since its the AM modulated part of the signal that will suffer more in poor reception conditions..." What you fail to understand, and it is quite complex, is that the AM modulated part is transmitted over the air as FM. Take the L and R signals filter to 15kHz and add them to give L+R and subtract them to give L-R. Generate a 19kHz tone. Double it to 38KHz. Use the 38kHz signal as the "carrier" in a double sideband suppressed carrier AM signal. (DSBSC) Add L+R + 19kHz + DBSSC to give the baseband signal and apply that to wideband FM modulator. The whole lot is transmitted as FM. In reception you receive the signal and demodulate the FM to get back the baseband. You use (normally) a PLL to lock to the 19kHz tone and double it to get a phase locked 38kHZ signal which is used to reinsert the suppressed 38kHZ carrier. You can then demodulate the difference and get L-R. Low pass filtering gives you the L+R signal. Add L+R + L-R to 2L Subtract L+R - L-R to get -2R and invert to get 2R. Job done. The stereo FM signal is massively wider in bandwidth than the equivalent mono meaning the signal to noise ratio is much worse. So IIRC you need about 23dB better signal strength for the same signal to noise ratio for stereo over mono. Due to the way FM works, a weak signal will be inherently nosier at higher frequencies which appears as hiss. FM audio is already pre-emphasised to minimise this, the gain rises with increasing frequency into the FM modulator. The interesting issue is human brains can accept and mask out a lot of the imperfections with analogue signals, we just learn to ignore the pops and hiss and hear the music still. Digital signals will sound "perfect" at signal levels that would be noisy for analogue. Then they drop off a cliff and you get burbles and break up and cant hear anything. The issue with DAB is it is an old crappy codec that doesn't compress the audio as well as modern codecs do. In order to maximise profit, signals are encoded at very low bit rates and strangled bandwidth to squeeze more in. So you get the worst of both worlds perfectly reproduced crap audio and no way to in-situ upgrade to better codecs. It is completely bogus. But hey never mind the quality... look at the choice of stations. Just that they all sound ****e. |
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Mono Stereo
On 22/04/2019 09:18, mm0fmf wrote:
The issue with DAB is it is an old crappy codec that doesn't compress the audio as well as modern codecs do. In order to maximise profit, signals are encoded at very low bit rates and strangled bandwidth to squeeze more in. So you get the worst of both worlds perfectly reproduced crap audio and no way to in-situ upgrade to better codecs. Someone calculated that intelligible speech could, if tokenized, be sent down a 50bps channel. I.e imagine reduing it to text or sylalables sending that, and re synthesing a voice at the other end. It is completely bogus. But hey never mind the quality... look at the choice of stations.Β* Just that they all sound ****e. Even FM **** is now ****e as the Beeb doesnt bother sampling its own feeds internally at high rates. -- You can get much farther with a kind word and a gun than you can with a kind word alone. Al Capone |
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Mono Stereo
In article ,
mm0fmf wrote: No. But DAB does sound ****e. Problem being having some expensive audio gear at home gets you used to stuff sounding good. The last car's original owner had fitted a £1200 audio upgrade which sounded fabulous on my high rate MP3s and CDs but the DAB was dire. FM sounded fine. Ages ago I put up some files of the same programme from DAB, FM and Freeview. Asked those who say DAB is **** to say which was which. Got the same results as using a pin. ;-) -- *No sentence fragments * Dave Plowman London SW To e-mail, change noise into sound. |
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