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.

--
When plunder becomes a way of life for a group of men in a society, over
the course of time they create for themselves a legal system that
authorizes it and a moral code that glorifies it.

  Frédéric Bastiat

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