From sweber@purdue.edu Sun Aug 06 06:51:34 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!purdue!sweber
From: sweber@purdue.edu (Seo-yeon Weber)
Newsgroups: comp.dsp
Subject: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Aug06.065134.1515@purdue.edu>
Date: Sun, 06 Aug 1995 06:51:34 GMT
Organization: Purdue University Engineering Computer Network
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Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier.

The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead.
This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks.

Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate.

-- 
Seo-yeon Weber -- Purdue University Engineering Computer Network
"Tape doesn't lie at 02:14. Ears do."

From dlaurent@mit.edu Sun Aug 06 20:38:34 1995
Path: ashpoly!cascade!mxgate!coyoacan!mit!dlaurent
From: dlaurent@mit.edu (Diego Laurent)
Newsgroups: comp.dsp
Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Aug06.203834.3199@mit.edu>
Date: Sun, 06 Aug 1995 20:38:34 GMT
References: <1995Aug06.065134.1515@purdue.edu>
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In article <1995Aug06.065134.1515@purdue.edu>, sweber@purdue.edu (Seo-yeon Weber) writes:
> Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier.

Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit!

My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise!

-- 
Diego Laurent
Tape trading list upon request. SASE required for international mail.