Design FM Receiver Circuit | 144-146Mhz Frequency Range

[aeterminator1]

I want to design a fm receiver circuit for the frequency range of 144-146Mhz.Kindly suggest me a suitable ic for the same.

 

[Averagesupernova]

One IC for a complete receiver in this range? What kind of receiver performance are you looking for? It just so happens I have a bit of experience in this area.

 

[Pumblechook]

Because narrow band FM (NBFM) is used on 144 MHz you can't use the standard 10.7 MHz IF directly.


I think all 'proper (sensitive)' NBFM receivers use double conversion to 10.7 MHz and then 455 KHz. You need a 11.155 MHz Xtal oscillator (10.7 + 0.455) OR 10.245 (10.7 - 0.455)

There is a circiuit here... Based on the MC3359 chip.

http://www.radioshop.co.uk/tech_articles/2mrx.htm

Also you need a narrow 10.7 MHz filter and a suitable 455 KHz one. As it is narrow band you need a much more stable first conversion oscillator...either Xtal controlled or synthesised. You need a 455 KHz quadrature coil for the de-modulation.

All in all it will be a far more complicated receiver than an FM broadcast one and cost considerably more.

 

[aeterminator1]

i need to design the circuit to decode a morse code which will be transmitted in this range,the IC TDA 7000 does not satisfy the frequency range criteria.It works in the range of 70 to 120 MHz range. Can i use a mixer to lower the incoming frequency to this range and than use it?

 

[waht]

Also check out the SA605 it's very similar to MC3359. It has a nice LNA on board, oscillator, mixer, and FM demodulator if needed.