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From: mball@noscvax.UUCP (Michael S. Ball)
Newsgroups: net.arch
Subject: Re: Floating pt. A/D converter
Message-ID: <1015@noscvax.UUCP>
Date: Mon, 15-Jul-85 17:08:44 EDT
Article-I.D.: noscvax.1015
Posted: Mon Jul 15 17:08:44 1985
Date-Received: Fri, 19-Jul-85 03:21:38 EDT
References: <293@eneevax.UUCP> <5600033@uiucdcsb>
Reply-To: mball@cod.UUCP (Michael S. Ball)
Organization: Naval Ocean Systems Center, San Diego
Lines: 26
Summary: 

In article <5600033@uiucdcsb> dollas@uiucdcsb.Uiuc.ARPA writes:
>
>To the best of my knowledge there is no such thing as a floating point
>A/D converter. The job of an A/D converter is to resolve an
>analog signal within a range to a binary number. Usually
>16 or 18 bits are about as good as you can get (and on top of that I 
>claim that even if you had more bits of accuracy there would be little
>use for them since the signals you are most likely to digitize are not
>that accurate, there is noise, etc).

Actually, there are floating point A/D converters.  They are used in
specialized applications like active sonar systems, where the dynamic
range may be up to 120 dB.  In such cases the exponent is provided
by some external device, usually driven from a clock.  The result is
still unnormalized, and must be further processed.  For most applications,
including almost all audio applications, 16 bits of raw data is quite
adequate.

This is not to imply that 16 bits is adequate for the signal processing,
as the number of significant bits can rise rapidly as the signal is
filtered.

-Mike Ball-

 TauMetric Corporation.
 San Diego, CA.