From rnilsson@netcom.com Wed Jan 18 13:28:24 1995
Path: ashpoly!cascade!transat!eunet-fr!teletel!netcom!rnilsson
From: rnilsson@netcom.com (Renata Nilsson)
Newsgroups: comp.dsp
Subject: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Jan18.132824.2688@netcom.com>
Date: Wed, 18 Jan 1995 13:28:24 GMT
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Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip.

By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample.
This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks.

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

-- 
Renata Nilsson
Tape trading list upon request. SASE required for international mail.

From ckang@inria.fr Fri Jan 20 03:59:24 1995
Path: ashpoly!cascade!transat!eunet-fr!teletel!inria!ckang
From: ckang@inria.fr (Camila Kang)
Newsgroups: comp.dsp
Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Jan20.035924.3872@inria.fr>
Date: Fri, 20 Jan 1995 03:59:24 GMT
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In article <1995Jan18.132824.2688@netcom.com>, rnilsson@netcom.com (Renata Nilsson) writes:
> Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip.

Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering.

-- 
Camila Kang | ckang@inria.fr
PGP Key fingerprint: 026D FE50 FA7E 1824
"Keep the channels open."