FM demudulation design

[SeungminLee]

Hi, there.

Recently, I’m trying to design FM transmitter and receiver system.
Transmitter should minimize power consumption so I use only VCO and antenna and transmitter range is only couple of meters.
However, designing receiver module, most commercialized FM receiver module transmits to PC by SPI or serial comm. As the signal I want to measure is distributed from 0.5 Hz to 1 kHz, I should convert to digital at least 4 kHz so I decided to employ external ADC board after demodulated analog output end. Block diagram I want to design is attached.

The question is here; all about demodulate circuit,

1. As I search ‘Analog FM receiver module’ on web sites, I only found basic FM circuit. Does it work correctly? Too much noise would be a big problem.

2. Is there any analog demodulating IC chip which you guys recommend? This is first time for me to design FM circuits. Please share your experience to me.

Thanks for reading the article and hope everything is going fine with you.

 

[betwixt]

It would be simpler to convert the analog signal to digital before transmitting it instead of transmitting analog and digitizing it after the receiver.

This would give you better noise immunity and make the transmitter and receiver circuits simpler. There are many modules on the market that will handle digital streams fast enough and they are inexpensive and power efficient.

If you want to stay with the present system, use a crystal controlled oscillator and amplitude modulate it. this will keep the frequency stable without needing to use a PLL. Over such a short range you can use a simple tuned circuit and diode (like a crystal set) as a receiver.

Brian.