HI Eugene, like Rob said, you would need to run the converters at 500 Msps, and then decimate down from there, which requires a super-sample capable DDC block. Such a block does not exist for RFNoC, at least not right now. The bigger issue is that the 500 Msps images are built for only two channels total (the 8-channel images top out at 250 Msps). Bottom line is, I think this is stretching the capabilities of X440 a bit too far.
You could try building an X4_200 image with 16 DDCs (make sure you reduce the number of halfbands to 1, and the max CIC depth to 5 to match your 500 -> 50 resampling requirement). Does that even fit onto the FPGA? If there should be any chance of making it work, this would have to fit with resources to spare. --M On Wed, Feb 4, 2026 at 8:57 PM Eugene Grayver <[email protected]> wrote: > Hi, > > I may be getting greedy but ... > > I want to record GPS signal with separate streams for L1 (at 1.6 GHz) and > L2 (at 1.2 GHz) Each signal is about 50 MHz wide by itself, but getting > both would require ~400 Msps. > > I need all 8 channels of the X440. > > Ideally, I would use the 200 MHz variant with **two** DDCs per channel. > One DDC for L1 and one for L2. That way the total sample rate would be > only 100 Msps (vs. 400). > > > - Would UHD support that? > - I assume it's a custom RFNoC build > > > Any suggestions on how to set that up? Would 16 streams even work? > > Thanks > > Eugene Grayver, Ph.D. > Principal Engineer > 310-336-1274 > _______________________________________________ > USRP-users mailing list -- [email protected] > To unsubscribe send an email to [email protected] >
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