Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!ucsd!nosc!manta!north
From: north@manta.NOSC.MIL (Mark H. North)
Newsgroups: sci.electronics
Subject: Re: A question about the Nyquist theorm
Message-ID: <1772@manta.NOSC.MIL>
Date: 19 Feb 91 03:57:49 GMT
References: <1758@manta.NOSC.MIL> <1759@manta.NOSC.MIL> <2189@umriscc.isc.umr.edu>
Organization: Naval Ocean Systems Center, San Diego
Lines: 17

In article <2189@umriscc.isc.umr.edu> robf@mcs213f.cs.umr.edu (Rob Fugina) writes:
>In article <1759@manta.NOSC.MIL> north@manta.NOSC.MIL (Mark H. North) writes:
>>Sorry to answer my own post but I take that last paragraph back. I think
>>you are wrong after all. Look at it this way -- suppose I tell you I'm
>>going to send you one of two signals, either 1 volt 60 Hz or a DC voltage
>>between -1 and 1 volt. You may sample at 120 Hz. You get all identical
>>samples at 0.5 volts. Which signal did I send?
>>Mark
>
>You sent a DC signal of 0.5 volts.  If it were AC, you the samples would
>be alternating positive and negative of the same magnitude.
>
Yes, thanks for pointing that out. How about all zero samples? Yes, I know,
pretty damn likely it was the DC signal. I think I made my point, you must
sample at >2nu to reconstruct the signal.

Mark