If you want to monitor anything passing through the audio subsystem -- note, some sound cards provide a hard bypass, but that's looping around the subsystem -- you can't ever get around a minimum of 1 buffer latency.
256 sample buffers / 192000 samples per sec = 1.3 ms latency. There will probably always be a way to patch signal around the audio subsystem so as to eliminate latency entirely. If you want to monitor what the audio subsystem and signal processing are doing, however, then some latency is always going to be there. You could provide a secondary digital path through the host computer that used, say, 64 sample buffers. 300 usec isn't bad. But you don't want to use those same 64 sample buffers for your filters, probably. So with minimum latency you won't be actually monitoring the processing, just your input. FireWire systems can likely get the absolute minimum down to around 10 samples. They still won't have passed through the processing in that case either, however. As long as the audio systems use buffered IO, the latency will never be completely eliminated. As long as you use FFT-based convolution for efficient filtering, the true latency will never be less than the length of the primary filters. 73 Frank AB2KT Jimmy Jones wrote: > Ya Ya---- > > I'm able to setup everything for speed as far as I can tell and the ssb > monitor is still terrible. > > Firebox @ 1.5ms > Firbox CPU on High > Audio and dsp set at 256 > and the program runs in realtime mode. > There are no skips on transmit or recieve. > I know a few people that wont buy the flex just because of that. What a shame. > I guess there will be a few cw geeks...uh freaks that won't buy the radio for > the same reasons.(latency) > From: Frank Brickle > To: FlexRadio@flex-radio.biz > Sent: Sunday, May 21, 2006 10:28 PM > Subject: Re: [Flexradio] Cw Latency Problem Solved? > > > Jimmy Jones wrote: > > I wish some of brain - o's could solve the monitor latency problem. > > Well, according to Science Today magazine this week, some string > theorists are speculating that time travel may actually be feasible. > > With that solved the monitor latency problem won't be far behind. Till > then, unfortunately, the only other solution is ESP. > > 73 > Frank > AB2KT > > _______________________________________________ > FlexRadio mailing list > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ > FlexRadio Homepage: http://www.flex-radio.com > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.1.392 / Virus Database: 268.6.1/344 - Release Date: 5/19/2006 > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/attachments/20060522/78089863/attachment.html > _______________________________________________ > FlexRadio mailing list > FlexRadio@flex-radio.biz > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ > FlexRadio Homepage: http://www.flex-radio.com > > _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://mail.flex-radio.biz/pipermail/flexradio_flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com
