Ian says:
>The difficulty with DDS spurs is that the amplitudes and
>frequencies change (pseudo) randomly with frequency.
No they don't. See the paper by Danielli of UCLA in IEEE (I think is it was
Circuits and Systems) back some ten years or so. They are predictable, although
it's complicated to do it. They tend to be worse where the multiplicand of the
minimum step size is of a value tending to 2*(n+/-m) where m is a small number.
This is a Diaphantine equation, of course.
I would have thought that anybody doing a real review these days would be using
IEEE bus controlled generators, not a 608 or an 8640, so a sweep shouldn't be
that hard to do.
73
Peter G3RZP
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