Discussion:
Propagation time
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RFguy
2008-05-06 23:41:15 UTC
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In circuit-switched cellular voice connections (I'm mainly interested in the
AT&T network) is the propagation time constant once the connection is
established? In other words, does the trunking involve IP connections?

Admittedly, I never notice changes in voice delays on cellular calls, but
I'm asking here about constant propagation times within 0.1 usec, much
smaller than the human ear can detect.

Thanks.
Andreas Wenzel
2008-05-07 22:52:50 UTC
Permalink
Post by RFguy
[...]
Admittedly, I never notice changes in voice delays on cellular calls, but
I'm asking here about constant propagation times within 0.1 usec, much
smaller than the human ear can detect.
You really mean 0.1micro-seconds? In that case it does not matter what
technology is used. Move one inch towards the tower and your delay
changes by about a micro second.

Andreas
Andreas Wenzel
2008-05-07 23:07:23 UTC
Permalink
Post by Andreas Wenzel
Post by RFguy
[...]
Admittedly, I never notice changes in voice delays on cellular calls,
but I'm asking here about constant propagation times within 0.1 usec,
much smaller than the human ear can detect.
You really mean 0.1micro-seconds? In that case it does not matter what
technology is used. Move one inch towards the tower and your delay
changes by about a micro second.
Opps, sorry, "slight" miscalculation. 0.1µs equals to about 100ft, not 1".

Andreas
RFguy
2008-05-08 00:47:04 UTC
Permalink
Yes, that's the accuracy I need. The application is very sensitive to
propagation time. The equipment will ping the circuit when the call is set
up in order to measure round-trip delay. What I want to know is, can the
delay change during the call because of IP packet delays? If IP isn't used,
that's what I need to know.
Post by Andreas Wenzel
Post by Andreas Wenzel
Post by RFguy
[...]
Admittedly, I never notice changes in voice delays on cellular calls,
but I'm asking here about constant propagation times within 0.1 usec,
much smaller than the human ear can detect.
You really mean 0.1micro-seconds? In that case it does not matter what
technology is used. Move one inch towards the tower and your delay
changes by about a micro second.
Opps, sorry, "slight" miscalculation. 0.1µs equals to about 100ft, not 1".
Andreas
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