I use POS-150 as oscillator for FM band (87.5-108 MHZ).
When modulate the oscillator with a MPX sound it plays well but does not make segregation in the channels , if I receive the oscillator with a stereo radio for Fm band. Only turn on the LED which is for to show when the station is stereo.
Why happen it ;
The POS-150 is a voltage controlled oscillator from Mini-Circuits.
savnik said:
When modulate the oscillator with a MPX sound it plays well but does not make segregation in the channels , if I receive the oscillator with a stereo radio for Fm band. Only turn on the LED which is for to show when the station is stereo.
Why happen it ;
It all depends what you mean by "MPX sound"?
I assume you mean a multiplex stereo signal.
How are you generating that multipexed signal?
Does it have the 38kHz (or is it 19khz?) pilot tone? If not the LED in the receiver won't illuminate.
I assume you mean a multiplex stereo signal.
How are you generating that multipexed signal?
Does it have the 38kHz (or is it 19khz?) pilot tone? If not the LED in the receiver won't illuminate.
Its modulation bandwidth is too narrow for FM stereo because it has an output down 3dB at 100kHz bandwidth. It must be absolutely flat to 38kHz for low audio frequencies stereo and it must be absolutely flat to 53kHz for audio frequencies up to 15kHz stereo.
In the "good old days" when an FM receiver's IF amplifier had a bandwidth that was too narrow for good separation of multiplexed stereo channels, an RC circuit was used in the audio path to boost the high frequencies up to 53kHz so that the response was flat. Then the stereo separation was very much improved.
I wonder how much it would help this RF transmitter.
In the "good old days" when an FM receiver's IF amplifier had a bandwidth that was too narrow for good separation of multiplexed stereo channels, an RC circuit was used in the audio path to boost the high frequencies up to 53kHz so that the response was flat. Then the stereo separation was very much improved.
I wonder how much it would help this RF transmitter.
The mini circuits pos series of VCO can not be modulated by frequencies much over 10 KHz. This is because the is internally a large bypass capacitor (.1 uF) directly on the control voltage pin to ground. This is the reason you are having problems.