Filtering an IF Signal

[djnik1362]

Hi
I'm working with an AM receiver project which in electronic parts I must accomplish this job :

Sampling of an IF signal centered at 140MHz with 1MHz bandwidth.
Rejection of adjacent channels must be 80dB (Signals Centered at 139MHz and 141MHz must attenuate 80dB).

I need a solution .

All processing could be done with FPGA.

Thanks for your support.

 

[FvM]

You'll use a combination of analog and digital filtering. Have a feasible bandpass, e.g. +/-2 to +/- 5 MHz stop band, band pass sampling with sufficient rate according to the Nyquist criterion, digital filters for the final receiver characteristic.

Alternatively sampling with high rate and purely digital filtering. Preferred implementation according to the available technology.