In message 
          The Natural Philosopher  wrote:

> On 27/06/2020 16:38, David Higton wrote:
> > In message 
> >            Jan Panteltje  wrote:
> >
> > > 30 MHz has a wavelength of 10 meter. for distances on an eurocard
> > > (100x160 mm) board the transmission line issue is not very significant.
> >
> > A common misconception is to relate these issues to the repetition rate.
> > It can be one cycle per fortnight, but if the transition times are short
> > (roughly a nanosecond or less), what arrives at the destination may have
> > more edges in it than were sent, unless the line is appropriately
> > terminated.
> >
> > Whether there is a problem also depends on the bandwidth/speed of the
> > receiver.
> >
> > David
> >
> yup. First job post uni was in a lab where we coupled up a signal
> generator to one end of a reel of coax, and used a twin beam scope to  look
> at what came out the other end. Direct evidence for te speed of  light! And
> pulse distortion. And reflection.

Aha.  At last, someone else who understands transmission lines.

David

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