In article ,
William Sommerwerck wrote:
"Dave Plowman (News)" wrote in message
...
In article ,
William Sommerwerck wrote:

But I'm still not sure what you mean by 'non linear group delay'.

Phase shift in which the shift is not linearly proportional to the
frequency, along a straight line that passes through the origin.

Right. And just where would you get this?

From less-than-well-designed transmission systems.

The US had microwave systems which generally had low group-delay errors.
In the late '50s, Europe had coax systems which generally did not. Which
was one of the reasons PAL was selected. According to the books, anyhow.

Thanks for the explanation. Could explain why I've not heard of it. In the
UK microwave links tended only to be used for linking say an outside
broadcast back to a receiving area. To transmitters is generally cable -
although one channel does use satellite. And of course satellite is
getting more common for the former task.

--
*When it rains, why don't sheep shrink? *

Dave Plowman London SW
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