Howdy, For FM/AM demod, you require a complex baseband. I am downconverting the IF from 1MHz to baseband by multiplying the input stream (12 bits) from the ADC with Sin and Cosine outputs of a DDS and therefore, generating I, Q I am using standard 18x18 signed multipliers in Xilinx to do the mixing. Is this right or should I use a complex multiplier? The reason why I am asking this question is because, I had implemented the whole datapath (Downconversion, Rate decimation, Compensating FIR) and verified it on the bench and then implemented CORDIC for getting FM, which never worked. So instead I tried to do AM demod by not using CORDIC but (Sq(I) + Sq(Q)) using standard 18x18 signed multipliers and still no AM demod which is supposed to be simple. Then I took the CIC and CFIR filters out and tried to do demod straight after the mixing, still nothing. So I'm kinda stuck here, any help will be appreciated Thanks
-M p.s. I don't have access to Matlab and System generator, but I'm buying them next week. I figured, doing digital radio design without modeling tools is like digging your own grave!!!