oversampling

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Dear MISC'ers

I have been reading the A/D conversion discussion and have seen
no mention a method which I thought of when I first heard that the
iTV box would contain a modem. If one would generate a sine wave via
D/A (1 bit oversampled and analog filtered) at the desired sampling
frequency (e.g. 4*3.6kHz or 15kHz) and input it as the reference level
into the A/D comparator, one could time between comparator toggles
using a counter like the F21c echo timer circuit. This reportedly could
resolve to 0.1ns which would equate to a 10GHz clock on the counter.
This would be 0.3M counts per half cycle or 18.5 bit resolution. Even
with a 1GHz clock on the counter, you could resolve 15 bits this way.
I am not an electronics person, so I don't know if this would actually 
work, any comments?

Mark
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 Mark Tillotson -- Head, Mechanical Design Group
 CTF Systems Inc.   Ph:  (604) 941-8561
 15-1750 McLean Ave.   Fax: (604) 941-8565
 Port Coquitlam, B.C.  email: markt@ctf.com
 Canada V3C 1M9   Web Page: http://www.ctf.com
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