[Elecraft] monitor delay

[Jim Brown]

On Fri, 15 Jan 2010 19:29:33 -0500, DOUGLAS ZWIEBEL wrote:

>Maybe most people simply don't complain?

ALL digital systems have some delay (known as "latency") for 
two reasons. First, there must be A/D and D/A conversion. 
Second, any DSP system requires some processing cycles to do 
what it does. The amount of latency (in msec) depends on the 
sampling rate, the bandwidth, the number of bits, the speed of 
the processors, how much processing is going on, and to some 
extent, the skill of the programmer. If both radios use DSP, 
their latencies are additive. 

We humans don't notice the delay unless we have something to 
compare it to. That can be the live sound of our own voice, or 
the audio from your transmitter monitored in another receiver. 
And we're sort of used to delay -- it takes time for sound to 
travel through the air, roughly 0.8msec per foot (varies a bit 
with temperature).  

The internet has a lot of latency -- 50-100msec is typical. 
This is one of the key issues with a remote station, and it 
makes contesting from a remote station a real challenge. 
Internet latencies are additive to the velocity of propagation, 
and are due to the TCP/IP protocols used to route data packets 
and the communications between equipment that routes those data 
packets. 

73,

Jim Brown K9YC