Re: DSP Implementation Woes

On 2008-01-31, brendan_online@xxxxxxxxxxx <brendan_online@xxxxxxxxxxx> wrote:
I push the chip to use the LPF implementation and see if at slightly
below the Nyquist rate the output works as I would expect it to within
a legitimate tolerance.

If you sample at 100Hz and try to produce a 49Hz output, there will be
an image at 51Hz. You have met the theoretical limit, but now you need
an analog filter that passes enough 49Hz and blocks enough 51Hz to meet
your needs. If you increase the sample rate to 200Hz, the image moves
up to 151Hz and now you can use a much simpler filter.

I'm not sure what you mean by "push the chip". Look up "reconstruction
filter".

--
Ben Jackson AD7GD
<ben@xxxxxxx>
http://www.ben.com/
.

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