There is an application which processes Complex I/Q signal of 100 MHz bandwidth and it is required to extract independent sub-bands from this bandwidth at different center frequencies and bandwidths. I wanted to ask what are the techniques which can be used to extract this sub-band data?

Edit: FFT can also be considered as a filter bank. Can the FFT information be used to create independent sub-band data using IFFT etc.?

  • $\begingroup$ I don't know what IQ signal is but I think a set of filter bank can solve your problem. $\endgroup$ – ZR Han Feb 9 at 0:57
  • $\begingroup$ @ZRHan Thanks for your response. I meant the signal is complex (In-Phase and Quadrature component). I also had the idea of filter banks in mind but was wondering if there are other methods as well. $\endgroup$ – malik12 Feb 9 at 6:15
  • $\begingroup$ Another idea is a frequency translation followed by a CIC decimation with a compensation FIR. Can you share what's your application? $\endgroup$ – gotchi85 Feb 9 at 13:53
  • $\begingroup$ @gotchi85 Thanks for your response, yes I think DDC can also be used for this purpose however how would that scale if a large number of channels are required e.g 50? $\endgroup$ – malik12 Feb 10 at 11:17
  • $\begingroup$ 50 DDC implemented inside an ADC+FPGA is possible. Another possible solution can be an acquisition board + PC + GPU. As always, implementation complexity depends of the spec $\endgroup$ – gotchi85 Feb 10 at 16:44

I wanted to ask what are the techniques which can be used to extract this sub-band data?

That's a description of a filter bank.

Yes, the FFT can be used for such applications. You'll find that OFDM, which powers DVB-T, 4G/5G, WiFi, … (basically all high-speed wireless terrestrial links) does exactly that.

You'll also find that if you find the inherent sinc-shape of subcarriers in an FFT filterbank insufficient, but still need regularly spaced channels, polyphase filterbanks are the way to go.

  • $\begingroup$ Thank you for the answer. I am relatively new to this area. Do the polyphase filter banks also perform sample rate conversion or would I need DDCs at the filter bank output for that purpose? $\endgroup$ – malik12 Feb 18 at 11:31
  • $\begingroup$ you can research that yourself within minutes. $\endgroup$ – Marcus Müller Feb 18 at 11:32
  • $\begingroup$ Ok. Thank you for your time. $\endgroup$ – malik12 Feb 18 at 11:45

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