Topband: DSP and Latency

[Herbert Schoenbohm]

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
>
>
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