ADC card selection for C6713

That 70 MHz is apparently an IF on a satellite receiver.

What is the signal like at 70 MHz ?

Is it band limited to less than 150 kHz or is the IF bandwidth maybe

1-10 MHz wide ?

Is it on a stable frequency say 70.000 MHz or does in drift +/- x MHz due to front end drift or satellite doppler ?

Is it a constant amplitude signal (after AGC or limiter) or does the signal amplitude vary 10-60 dB ?

Do you intend to sample the 70 MHz IF signal (directly or decimating) or do you get rid of the PM in ordinary analog circuits and digitise the 65 kHz subcarrier ?

Paul

Paul Keinanen yazdi:

It is bandlimited to 138 khz. But I want to design a system which can manage wider bw. Because wider be may be used in future .

I think it as stable 70 mhz up to this time. There may be countable effects and if you want to learn especially for it I can learn and say to you.

AGC has to be used before ADConversion.

According to subsamplig rate (any value between 250-500khz) I intend to sample it.

65 kHz carrier is BPSK subcarrier. Before BPSK I have to do PM demodulation.

If you think to help me we can talk closely by msn or private mailings.

16x samplings of the subcarrier would be approx. 1msps.

You need that to clock the digital PLL.

It doesn't matter, you just need it to clock your logic.

Just upgrade to faster parts in the future. You can never design a product for the future, unless you are in the movie business.