There is a very straightforward fix for this latency.
Simply use a POTS telephone line with a phone patch.
Receive audio comes in, and CW tones go out. At
the remote site, a tone decoder generates key closures.
I measured 50 ms latency on a 100 mile phone connection.
And you never get audio glitches.
Rick N6RK
On 3/18/2015 7:38 AM, Bill Cromwell wrote:
Hi Jim,
I have begun playing with soundcard SDR and DSP software. "Latency"
varies all over the place (from config to config) and can be somewhat
managed. The real sticking place for me is the delay between pressing
the key (CW of course) and the beginning of the dit or dah. Again when
releasing the key and the end of the dit or dah. When the radio is right
in front of me, I can use an external 'sidetone' and coordinate my
keying hand with that. I am not sure how that is handled with a remote
station setup. Perhaps the remote user is using a local sidetone or even
sending with a keyboard. If it's computer generated CW from the keyboard
any 'latency' just won't matter. It's milliseconds or less - not minutes
or hours.
Maybe this comment will help some others get a better handle on this
'latency'.
73,
Bill KU8H
On 03/18/2015 07:27 AM, Jim Brown wrote:
On Wed,3/18/2015 12:14 AM, Mark van Wijk, PA5MW wrote:
Audio latency 'differences' can be shown in the shack already;
Yes. I mentioned that A/D and D/A conversions take time. So do DSP
processes. The word that describes this time is latency. It is not
limited to audio.
I had to learn about all of this more than 20 years ago, because I
worked in pro audio, when we began to use DSP extensively in large
sound systems.
73, Jim K9YC
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