FMCW Demodulation at Higher Bandwidths

[SAIKIRAN_GOVINDU]

I’m trying to perform FM demodulation on FM signal using RF communication FPGA drivers which are available. Input FM signal is sent to the FPGA through the Host to target FIFO and the Demodulated is sent back to the host using Target to Host FIFO. The desired bandwidth for the demodulation operation is greater than 200 MHz.

I am able to achieve demodulation when the bandwidth is set to 96MHz or lower, at Bandwidths greater than 96MHz output is getting distorted, i suspect that  it is because wrapping of the output data .

Demodulation pictures are attached here

fig 1. shows for 96MHz bandwidth.

fig 2. shows for 160MHz bandwidth

fig 3. shows the implementation of FPGA code of FM demodulation.

Any help on this would be greatly appreciated. Thanks in advance

[l.hovs]

Hi SAIKIRAN_GOVINDU, 

To be clearer, can you share your LabVIEW code with us? For now, I guess there could be a few reasons causing this issue. 

1. Considering your distorted output signal, I ask you to check your sample rate, if that is less than twice your carrier signal's frequency (for example you have 200MHz the sample rate should be a 400) then you should put the sample rate equal to twice your carrier signal's frequency (in your case if you want to achieve suitable results, you should put sample rate 400 or grader).
2. Going back to the modulation. Are you sure that your data is correct coming out from your modulation? Check is it correct or might be the problem comes from that.

3. Does the demodulation doing mixer conversion or doing a direct digital conversion?

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Regards)