[Flexradio] Filters... is it just me?
Ever since i upgraded to v2.0.20 I keep thinking the Rx SSB filters are not as sharp as the were on v2.0.19 and below. I am running the DSP RX filter at 4096 as before, but does not seen as sharp. Has anyone else questioned this? Joe N9VX Flex 5000A, Lenovo Core 2 Duo, 2gig ram, XP , nothing but PowerSDR runs on the computer. ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/
Re: [Flexradio] Filters... is it just me?
On Fri, Mar 25, 2011 at 6:31 AM, Joe Word joe.n...@gmail.com wrote: Ever since i upgraded to v2.0.20 I keep thinking the Rx SSB filters are not as sharp as the were on v2.0.19 and below. I am running the DSP RX filter at 4096 as before, but does not seen as sharp. Has anyone else questioned this? There is no change in that area that I have been able to see. Did you change sample rate? Filter sharpness is determined by both sample rate and DSP RX buffer size. If you double the sample rate it is the same as cutting your DSP RX buffer in half. -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 br...@lloyd.com +1.767.617.1365 (Dominica) +1.931.492.6776 (USA) (+1.931.4.WB6RQN) ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/
Re: [Flexradio] Filters... is it just me?
On Fri, Mar 25, 2011 at 9:19 AM, Brian Lloyd brian-wb6...@lloyd.com wrote: On Fri, Mar 25, 2011 at 9:05 AM, Joe Word joe.n...@gmail.com wrote: Brian, Thanks for the reply, so for sharp filters we need RX Buffers large and Audio/Sample Rate low. I have not experimented much with the Sample Rate and may have had it too high, it was at 19,200 so changed it to 4800. That will certainly do it. When I need really sharp filters then I do just that. OTOH, I find that a sample rate of 96kHz with 4096 sample DSP buffers is more than adequate for all but the narrowest of modes. Also remember that, the sharper you make your filters, the more delay or latency you introduce to the signal. For phone and most digital modes it won't matter. For CW, PACTOR, and ARQ (flarq) digital modes it can be critical. Again, it is a matter of personal preference. But it is nice to be able to tune that. -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 br...@lloyd.com +1.767.617.1365 (Dominica) +1.931.492.6776 (USA) (+1.931.4.WB6RQN) -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 br...@lloyd.com +1.767.617.1365 (Dominica) +1.931.492.6776 (USA) (+1.931.4.WB6RQN) ___ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flexradio.com/ Homepage: http://www.flexradio.com/
