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Stereo Separation Alignment FM Radio - Is this possible with TinySA?

 

I understand that there are no plans for the signal generator in the TinySA (I have the Ultra version) to gain the functionality of modulating the carrier with an FM stereo composite signal. Is there another method for aligning a FM radio's stereo separation using the TinySA without any other specialized equipment (except perhaps a scope)?

If yes, what would the steps be to do that?

Thanks!

Roy
 

The SA can be used to view the stereo sidebands from an FM broadcaster over the air.? How this relates to alignment of a receiver separation is beyond me.

There are specialized instruments that generate the stereo signal.? I'd check ebay for something inexpensive from China.

Dave - W?LEV ?

Dave - W?LEV


On Fri, Jan 20, 2023 at 6:07 AM Roy - KI0ER via <ki0er=[email protected]> wrote:

I understand that there are no plans for the signal generator in the TinySA (I have the Ultra version) to gain the functionality of modulating the carrier with an FM stereo composite signal. Is there another method for aligning a FM radio's stereo separation using the TinySA without any other specialized equipment (except perhaps a scope)?

If yes, what would the steps be to do that?

Thanks!

Roy



--
Dave - W?LEV
 

The stereo audio signal modulating the FM carrier consists of the combined channels and a 19 KHz pilot signal used to synchronize the channel switching during separation of the audio into separate channels.? I believe the resolution of the TinySA is inadequate to resolve the precision required for alignment.? This would require the audio frequency equivalent of the TinySA.

?

A NanoVNA might be used for an analog discriminator, but not likely for a PLL type.
 

There are quite a number of audio SAs online as freeware.? Pick the one that best suits your needs.

The TinySA Ultra specification for minimum RBW is 200 Hz.? This should be more than adequate to view the stereo sidebands off the air.

Dave - W?LEV


On Sat, Jan 21, 2023 at 5:00 PM Neil Preston W0NRP via <w0nrp=[email protected]> wrote:

The stereo audio signal modulating the FM carrier consists of the combined channels and a 19 KHz pilot signal used to synchronize the channel switching during separation of the audio into separate channels.? I believe the resolution of the TinySA is inadequate to resolve the precision required for alignment.? This would require the audio frequency equivalent of the TinySA.

?

A NanoVNA might be used for an analog discriminator, but not likely for a PLL type.



--
Dave - W?LEV
 

I believe that there are apps for audio spectrum analysis for the PC (I know that there are some for Android) that would have the resolution required to do what you want.
 

Way back in my college days I had a pirate FM radio station (made from a Radio Shack FM transmitter kit) and I didn't know how to build a stereo multiplexer circuit.? But I did know that if I injected a 19KHz audio signal on the carrier it would make the red "STEREO" indicator light come on in a FM receiver.? Not sure if the students in the dorms listening to my station caught on to the fact that none of the stereo songs I broadcasted were really just in mono!

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