I'm a bit confused by your calculation. Nyquist for complex data is equal to the analog bandwidth so you only need a sample rate of 25.6 MSPS as stated. USB 3.0 will handle this without a problem on the B200. If you use short (16 bit integers) IQ then you have 4 bytes/complex sample so ~100MB/sec.
I think solving your USB 3.0 woes and using GR on a general purpose processor will save you significant development time over FPGA implementations. Paul Garver On Sep 26, 2016, at 7:53 PM, "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>> wrote: duane> It seems like a perfect fit for a poly phase filter - however this is duane> something that I believe needs to be done in hardware (128 channels * duane> 200khz = about 60mhz sample rate this will not go over a USB cable, and duane> I doubt I can get this bandwidth into a laptop PC. sylvain> !?!? sylvain> 128 channels of 200 kHz = 25.6 MHz of bandwidth. You can totally get sylvain> that to a laptop. Nyquest requires 2x samples = 51.2mhz sample rate Assuming I/Q data 2x bytes = 102.4mbyte/second At 8bit bytes = 819.6 mbits per second is the bit rate. thats about 17% of the bandwidth of USB 3 (5gbit) however that does not account for framing overhead, and other related things. Figure another 10% loss for signaling over head. You are correct it is possible sylvian> B2xx or BladeRF will do that without issues given a sufficiently good laptop. You mean a USB 3 based solution possibly - but I have had very limited success with USB 3 - they always seem to fall back to USB 2 speeds, and/or - the data rate is not there - perhaps my experience is flawed due to cheap data sources {ie: hard drives} sylvian> If the transmission are "infrequent" you can even use the same trick sylvian> that researchers used a while back to listen to all of bluetooth and sylvian> deliberately alias the signal to fold the spectrum over itself. I understand that, after 'unfolding' I need to get the actual channel number. that's not possible if I do what you describe. duane> Am I going to have to do FPGA work on my own? sylvian> Very likely. duane> Or - is there some existing cook book solution with the FPGA duane> configuration pre-cooked? sylvian> Very unlikely to find something "all done". sylvian> Especially that if you don't want to ship the samples, a PFB is not sylvian> all you need. You'd need demod for each channel in the hardware as sylvian> well. That is well understood. duane> What I am looking for is the FPGA channelizer solution... hopefully an duane> existing one I could start with? sylvian> There is an embryon of one in the ettus rfnoc repo and AFAIK they sylvian> might also replace it with another version soon. sylvian> But it's written for RFNoC and Series-7 Xilinx fpga. It'll need quite sylvian> some adaptation to run on anything else. sylvian> Also, AFAIU, it's incomplete and non-tested currently so ... YMMV. Thanks for the pointer. -Duane. _______________________________________________ Discuss-gnuradio mailing list [email protected]<mailto:[email protected]> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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