On 5/10/05, Michael Rigby-Jones <Michael.Rigby-Jones@bookham.com> wrote:
> 
> The fact that the PCB size and the wavelength of the fundamental
> frequency are subtantialy different does not make the design immune from
> problems!  If it is a 1MHz square wave with fast rise fall times the
> harmonics will extend to very high frequencies.  Even at the 1MHz
> fundamental, stray capacitances and inductances can start causing
> problems.

Strays will not cause problems with the layout shown.

If you have overtones, than you are higher than 1MHz in frequency,
aren't you?  If you have a perfect square wave, than there are odd
frequency components to infinity!

In engineering, the first task is to decide which effects are
important, and which can be ignored.  It shows failure in this task to
tell the original poster that he shouldn't make angles in the traces. 
It is also unhelpful to focus an addmitted newbie's attention on
things irrelevant to their design.

Anyway, my point was that the board at the start of this thread has
perfectly reasonable layout for the frequencies involved with short,
direct traces.  (The ground path, however, needs a *lot* of
attention!)

Regards,
Mark
markrages@gmail
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