On Wed, May 14, 2008 at 11:09 PM, Ray J <[EMAIL PROTECTED]> wrote: how long do the buffers take to fill after the relay closes? > > I set my sdr1k to the fastest buffers, and listen to my Icom 746 > sending cw.. the relay closeson the 746.. it sends a dit, and the radio > just starts to receive again before I can hear the signal in my srd. > > I cannot see how that lag problem will be overcome...
It can't. The latency that's solved is entirely from the point of view of the operator, the lag between the end of a sidetone-sounding element and the resumption of received signal. Purely from the standpoint of QSK, that's the lag that counts. Where this can be minimized is in not emptying and refilling the buffers. With full duplex the buffers are kept full with causal signal, so the audio output sent to the user can be switched at the lowest latency in the system. So, all of the lags on signals arriving at the receiver will be consistent once they get to your antenna. But before the signals get to you, they will have been subjected to essentially random delays due to the different paths they take between their antennas and yours. So it's not like there aren't delays in signal arrival already, messing with your mind in familiar ways. Still, all of them, and your keying sidetone too, will be time-shifted by a *constant, miniscule* amount, and that's the key ingredient in smoothing the QSK. The CW ops at the great coastal maritime stations were dealing with transmitters located many miles from their operating positions, keyed with cascades of relays over phone lines, and with TX and RX antennas similarly located at separate sites. For that reason among others, I suspect that "perfect QSK" allows a lot more flexibility than we've been stipulating here. I further suspect that a lot of *perceived* perfection of QSK is actually an illusion sustained by other factors in the switching. 73 Frank AB2KT > > > > > Frank Brickle wrote: > > On Wed, May 14, 2008 at 11:59 AM, Jerry Flanders <[EMAIL PROTECTED] > > > > wrote: > > > > > >> If I understand Frank correctly, we will not see what CW ops call QSK in > >> PowerSDR/Windows. Ever. > >> > > > > That's not right. The entire audio subsystem inside the SDR software is > > being replaced. The new subsystem is common across all of the platforms, > > Windows included. It provides latencies as small as 64 samples. This > isn't > > speculation; it already exists. > > > > What you're not going to see is the new audio subsystem merged with the > old > > monolithic PowerSDR codebase. > > > > 73 > > Frank Brickle > > AB2KT > > > > > > _______________________________________________ > 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://kb.flex-radio.com/ Homepage: > http://www.flex-radio.com/ > > -- The only thing we have to fear is whatever comes along next. -- Austin Cline _______________________________________________ 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://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/
