From edubois@hanse.de Mon Nov 14 06:56:26 1994
Path: ashpoly!cascade!bigsur!hanse!edubois
From: edubois@hanse.de (Élodie Dubois)
Newsgroups: comp.dsp
Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1994Nov14.065626.4539@hanse.de>
Date: Mon, 14 Nov 1994 06:56:26 GMT
Organization: Hanse-Netzwerk Hamburg
NNTP-Posting-Host: hanse.de
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Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems.

The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead.
However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop.

Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip?

-- 
Élodie Dubois | edubois@hanse.de
PGP Key fingerprint: 61C9 4214 5A4A B0B3
"Keep the channels open."

From akim@delphi.com Wed Nov 16 10:53:26 1994
Path: ashpoly!cascade!mxgate!coyoacan!delphi!akim
From: akim@delphi.com (Astrid Kim)
Newsgroups: comp.dsp
Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1994Nov16.105326.2556@delphi.com>
Date: Wed, 16 Nov 1994 10:53:26 GMT
References: <1994Nov14.065626.4539@hanse.de>
Organization: Delphi Internet Services
NNTP-Posting-Host: delphi.com
X-Newsreader: Netscape 1.1N
Lines: 11

In article <1994Nov14.065626.4539@hanse.de>, edubois@hanse.de (Élodie Dubois) writes:
> Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems.

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

Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns.

-- 
Astrid Kim
Opinions expressed are solely my own and not those of Delphi Internet Services.
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