Topband
[Top] [All Lists]

Re: Topband: DSP and Latency

To: topband@contesting.com
Subject: Re: Topband: DSP and Latency
From: Herbert Schoenbohm <herbs@vitelcom.net>
Date: Tue, 17 Mar 2015 19:03:27 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
I listen here to Yuri N2TTA operate my remote contest station NP2P (SO2R) here from his apartment in NYC. My latency to his location is about 120 ms and the link is end to end fiber which travels at about 124,000 miles per second. I can not detect any delay nor problems even when he is running stations at 200 or more q's per hour at 40 wpm. It is really an improved technology via the internet. But ironically since fiber is slower than microwave, end to end stock market traders who have set up microwave links to Chicago from Wall Street are able to make fortunes by using a faster speed and scooping up transactions by arriving a few ms ahead of the orders coming in via fiber. Amazing stuff I think that Albert Einstein even studied the possibility of having matter travel faster than light. Right now all we have working is mental telepathy which reminds me of some of my 160 meter DX QSO's in 40db over S9 tropical QRN.☺


Herb Schoenbohm, KV4FZ
On 3/17/2015 5:41 PM, Jim Brown wrote:
On Tue,3/17/2015 12:48 PM, Frank Bogers - ON9CC / PA9A wrote:
Audio latency can be solved by DSP.

What do you mean "solve?" Latency is TIME -- more specifically, it is the time it takes electrical signals to get from point A to point B. If digital transport is involved, there is also the time it takes to convert from A/D and D/A. Transmission via radio is at the speed of light. Transmission via the internet is much slower, because of routing protocols and the equipment needed to implement them.

Typical internet latencies are in the range of 100 msec, so you're a bit behind. DSP can ADD delay, so that two signals are more nearly in sync, but it cannot REMOVE delay.

Also, ALL signals are delayed -- CW, RTTY, control signals, not just audio.

73, Jim K9YC


_________________
Topband Reflector Archives - http://www.contesting.com/_topband

_________________
Topband Reflector Archives - http://www.contesting.com/_topband
<Prev in Thread] Current Thread [Next in Thread>