Newsgroups: sci.electronics
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: Truth about "18-bit" digital audio products
Message-ID: <1989Jul16.053339.16435@utzoo.uucp>
Organization: U of Toronto Zoology
References: <19037@vax5.CIT.CORNELL.EDU>
Date: Sun, 16 Jul 89 05:33:39 GMT

[followup shifted to sci.electronics as this is not audio-related]

In article <19037@vax5.CIT.CORNELL.EDU> max@london.ee.cornell.edu  (Max Hauser) writes:
>Q:  "Well, then, why not add a few more successive-approximation cycles,
>and call it `22' -- was it pin-limited? -- or `24' bits ..."

And then of course there is the HP 3458A digital multimeter, which has a
28-bit ADC.

Really.

This thing is the most precise voltmeter ever built, with 8.5-digit
resolution.  (The converter actually puts out 32 bits, but the last few
are too noisy to be useful.)  It has to be calibrated with Josephson
junctions.  Most of the April 1989 issue of the Hewlett-Packard Journal
was about it.  Truly an amazing device; the price tag must be stupefying.

To cap it off, flip it into low-resolution mode and the same ADC does
16-bit conversions at 100 kHz.
-- 
$10 million equals 18 PM       |     Henry Spencer at U of Toronto Zoology
(Pentagon-Minutes). -Tom Neff  | uunet!attcan!utzoo!henry henry@zoo.toronto.edu