From jjohansson@kiae.su Sat Mar 25 18:14:58 1995
Path: ashpoly!bigsur!pacrim!jpgate!kamome!kiae!jjohansson
From: jjohansson@kiae.su (Ji-woo Johansson)
Newsgroups: comp.dsp
Subject: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Mar25.181458.8871@kiae.su>
Date: Sat, 25 Mar 1995 18:14:58 GMT
Organization: Kurchatov Institute of Atomic Energy, Moscow
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Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip.

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

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

-- 
Ji-woo Johansson
Tape trading list upon request. SASE required for international mail.

From jlindqvist@hanse.de Sun Mar 26 03:40:58 1995
Path: ashpoly!cascade!transat!eunet-fr!teletel!hanse!jlindqvist
From: jlindqvist@hanse.de (Jen Lindqvist)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Mar26.034058.2818@hanse.de>
Date: Sun, 26 Mar 1995 03:40:58 GMT
References: <1995Mar25.181458.8871@kiae.su>
Organization: Hanse-Netzwerk Hamburg
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In article <1995Mar25.181458.8871@kiae.su>, jjohansson@kiae.su (Ji-woo Johansson) writes:
> Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip.

Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in.

-- 
Jen Lindqvist -- Hanse-Netzwerk Hamburg
"Hardware is temporary. The signal survives."

From lduarte@purdue.edu Mon Mar 27 20:55:58 1995
Path: ashpoly!cascade!bigsur!purdue!lduarte
From: lduarte@purdue.edu (Lucia Duarte)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Mar27.205558.4245@purdue.edu>
Date: Mon, 27 Mar 1995 20:55:58 GMT
References: <1995Mar25.181458.8871@kiae.su> <1995Mar26.034058.2818@hanse.de>
Organization: Purdue University Engineering Computer Network
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In article <1995Mar26.034058.2818@hanse.de>, jlindqvist@hanse.de (Jen Lindqvist) writes:
> Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in.

Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in.

-- 
Lucia Duarte -- Purdue University Engineering Computer Network
"A soul is not exclusive to biology."