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Reply-To: "Kevin Aylward"
From: "Kevin Aylward"
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Subject: Re: How does a mixer work?
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Date: Tue, 22 Oct 2002 16:18:25 +0100
NNTP-Posting-Date: Tue, 22 Oct 2002 16:18:32 BST
"Chuck Simmons" wrote in message
> Kevin Aylward wrote:
> > The mathematics "prove" that there is an inherent measurement
> > the real world. You cannot measure frequency 100% accurately,
> > taking infinite time.
> No, you are reversing the implication. The "proof" of your statement
> requires inserting an underlying physical context which is not in the
> mathematics. The physical context spuriously inserted is physical
> measurement error.
You misunderstand the basics. The uncertainty relation (Dt.Df>=1/2)has
nothing to do with a physical measurement error, in the sense of using
imperfect equipment. The assumption is that the measuring equipment is
ideal. The issue is with the representation of signals.
In one case a signal is being characterised in the frequency domain, and
in the other the signal is being characterised in the time domain. The
mathematics show that these domains are not completely compatible.
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.
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