Re: oversampling
- To: "'MISC@xxxxxxxxxxxxxxxxxxxx'" <MISC>
- Subject: Re: oversampling
- From: Mark Tillotson <markt@xxxxxxx>
- Date: Fri, 9 Jan 1998 14:35:31 -0400
- Old-Date: Fri, 9 Jan 1998 10:33:10 -0800
- ReSent-Date: Fri, 9 Jan 1998 13:38:04 -0500 (EST)
- ReSent-From: Penio Penev <penev@xxxxxxx>
- ReSent-Message-ID: <Pine.SGI.3.96.980109133804.24742L@venezia.rockefeller.edu>
- ReSent-To: MISC
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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