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FM Analyzer - channelsepareation for stereocoder

cickel, 6.11.2009, 00:14, 84.128.30.190
channelsepareation for stereocoder

Hi Jan,
I have a question regarding the FM Analyzer.

Is it possible to upgrade the FM Analyzer to measure the channel sepereation from a stereocoder.

I have following in mind.
When the audio level of a stereocoder is measuring on each channel seperate, I would like to have the sepereation in dB by FM Analyzer.
Is this possibile?

Thanks in advance, best regards.

cickel

Jan, 6.11.2009, 09:55
Re: channelsepareation for stereocoder

No, this feature was not included in the design since measuring method for this very complex parameter is different and moreover there is no "channel separation" adjust on professional stereo encoders. No device of this kind measures real channel separation.

emerson, 6.11.2009, 10:23
Re: channelsepareation for stereocoder

It is physically impossible due to the fact that channel separation of any professional stereo coder is always much better than channel separation of any FM receiver. You must measure directly on the stereo coder output and use special method. For the illustration, the method becomes extremelly complicated when you want to detect channel separation of more than 60 dB and it's practically impossible to detect a separation of 70 dB or more. Where 70 dB or higher separation is mentioned in the stereo coder specification list, the parameter is only a result of a fantasy because in practice no measuring method exists to validate the value.

Bojcha, 14.12.2009, 22:04, 93.87.115.234
channelsepareation for stereocoder

i disagree..
Simply...
Use Mpxtool and good soundcard with 192kHz input (i use Juli@) calibrate mpxtool! .. then put mpx output into soundcard input, turn of L or R channel on stereo coder and watch mpxtool.

Jan, 15.12.2009, 08:54
Re: channelsepareation for stereocoder

I think you are both true but Bojcha writes about something different than the FM modulation analysis is. At the end of the path stereo encoder - cable - modulator - free space - receiver - demodulator the original channel separation is simply lost and cannot be recovered.

Bojcha, 15.12.2009, 16:11, 93.86.67.246
channelsepareation for stereocoder

True,
MPX out from best stereo encoder i can found, acording from MpxTool, there is ~24dB separation.. from best Tuner i can found same Stereo Encoder have 22dB ...
With some generated MPX from some broadcasting software for PC i can measure 45dB separation and from tuner 40dB, which is more then enough.
The worst tuners are Car-Radios, most of them have under 18dB separation.

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