FPGA System A modulator

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FPGA System A modulator

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ppppenguin

Senior Engineer in Charge

Posts: 7,656
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Location: London N12

#34

25-11-2018, 06:22 PM

It's actually quite difficult to do really good filtering. Depends heavily on the ratio sampling frequency to highest required output. If you've got 8x available (say 360MHz for channel B1) then the filter is dead easy. If you've got 4x (180MHz) then it's not too bad but a simple filter will start to show irregularities. These probably won't matter in terms of practical performance. As you come down from 4x towards the Nyquist limit of 2x it just gets worse. A lot worse. Frank is working around 4x so I'm not surprised. I don't think it's worth improving the filter at this stage. What you win on frequency response you usually lose on group delay or phase response.

www.borinsky.co.uk Jeffrey Borinsky www.becg.tv

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Messages In This Thread

FPGA System A modulator - by `FRANK.C - 17-11-2018, 01:06 PM

RE: FPGA System A modulator - by ppppenguin - 17-11-2018, 02:12 PM

RE: FPGA System A modulator - by `FRANK.C - 17-11-2018, 04:05 PM

RE: FPGA System A modulator - by Freya - 17-11-2018, 05:05 PM

RE: FPGA System A modulator - by Murphyv310 - 17-11-2018, 07:42 PM

RE: FPGA System A modulator - by ppppenguin - 17-11-2018, 07:51 PM

RE: FPGA System A modulator - by ppppenguin - 17-11-2018, 09:01 PM

RE: FPGA System A modulator - by `FRANK.C - 17-11-2018, 11:11 PM

RE: FPGA System A modulator - by ppppenguin - 18-11-2018, 07:03 AM

RE: FPGA System A modulator - by ppppenguin - 18-11-2018, 08:30 AM

RE: FPGA System A modulator - by ppppenguin - 18-11-2018, 10:24 AM

RE: FPGA System A modulator - by `FRANK.C - 18-11-2018, 09:33 PM

RE: FPGA System A modulator - by ppppenguin - 19-11-2018, 06:42 AM

RE: FPGA System A modulator - by `FRANK.C - 19-11-2018, 01:40 PM

RE: FPGA System A modulator - by ppppenguin - 19-11-2018, 02:11 PM

RE: FPGA System A modulator - by Nick - 19-11-2018, 02:29 PM

RE: FPGA System A modulator - by ppppenguin - 19-11-2018, 03:10 PM

RE: FPGA System A modulator - by `FRANK.C - 19-11-2018, 10:58 PM

RE: FPGA System A modulator - by ppppenguin - 20-11-2018, 09:22 AM

RE: FPGA System A modulator - by Terry - 20-11-2018, 09:59 AM

RE: FPGA System A modulator - by ppppenguin - 20-11-2018, 10:29 AM

RE: FPGA System A modulator - by Terry - 20-11-2018, 05:19 PM

RE: FPGA System A modulator - by ppppenguin - 20-11-2018, 11:08 AM

RE: FPGA System A modulator - by `FRANK.C - 20-11-2018, 06:58 PM

RE: FPGA System A modulator - by ppppenguin - 20-11-2018, 09:48 PM

RE: FPGA System A modulator - by `FRANK.C - 24-11-2018, 07:01 PM

RE: FPGA System A modulator - by Terry - 24-11-2018, 08:50 PM

RE: FPGA System A modulator - by Murphyv310 - 24-11-2018, 07:09 PM

RE: FPGA System A modulator - by ppppenguin - 24-11-2018, 09:35 PM

RE: FPGA System A modulator - by `FRANK.C - 25-11-2018, 10:07 AM

RE: FPGA System A modulator - by ppppenguin - 25-11-2018, 02:25 PM

RE: FPGA System A modulator - by Murphyv310 - 25-11-2018, 02:35 PM

RE: FPGA System A modulator - by Freya - 25-11-2018, 02:44 PM

RE: FPGA System A modulator - by ppppenguin - 25-11-2018, 06:22 PM

RE: FPGA System A modulator - by `FRANK.C - 25-11-2018, 06:51 PM

RE: FPGA System A modulator - by ppppenguin - 25-11-2018, 07:06 PM

RE: FPGA System A modulator - by `FRANK.C - 25-11-2018, 07:47 PM

RE: FPGA System A modulator - by ppppenguin - 25-11-2018, 09:42 PM

RE: FPGA System A modulator - by `FRANK.C - 25-11-2018, 11:19 PM

RE: FPGA System A modulator - by ppppenguin - 26-11-2018, 07:01 AM

RE: FPGA System A modulator - by `FRANK.C - 26-11-2018, 08:03 PM

RE: FPGA System A modulator - by ppppenguin - 28-11-2018, 02:51 PM

RE: FPGA System A modulator - by ppppenguin - 28-11-2018, 03:50 PM

RE: FPGA System A modulator - by ppppenguin - 28-11-2018, 04:59 PM

RE: FPGA System A modulator - by `FRANK.C - 28-11-2018, 06:27 PM

RE: FPGA System A modulator - by ppppenguin - 28-11-2018, 07:15 PM

RE: FPGA System A modulator - by `FRANK.C - 28-11-2018, 11:11 PM

RE: FPGA System A modulator - by ppppenguin - 29-11-2018, 07:32 AM

RE: FPGA System A modulator - by ppppenguin - 05-12-2018, 11:38 AM

RE: FPGA System A modulator - by `FRANK.C - 05-12-2018, 08:31 PM

RE: FPGA System A modulator - by ppppenguin - 05-12-2018, 10:06 PM

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