From ehernandez@hanse.de Thu Dec 07 21:29:36 1995
Path: ashpoly!cascade!brgate!saturno!hanse!ehernandez
From: ehernandez@hanse.de (Élodie Hernández)
Newsgroups: comp.dsp
Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Dec07.212936.7569@hanse.de>
Date: Thu, 07 Dec 1995 21:29:36 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.
The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead.

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

-- 
Élodie Hernández
Tape trading list upon request. SASE required for international mail.

From elindqvist@unam.mx Sat Dec 09 10:43:36 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!unam!elindqvist
From: elindqvist@unam.mx (Élodie Lindqvist)
Newsgroups: comp.dsp
Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Dec09.104336.7967@unam.mx>
Date: Sat, 09 Dec 1995 10:43:36 GMT
References: <1995Dec07.212936.7569@hanse.de>
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In article <1995Dec07.212936.7569@hanse.de>, ehernandez@hanse.de (Élodie Hernández) 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.

-- 
Élodie Lindqvist -- Universidad Nacional Autónoma de México (DGSCA)
"Marcus is not one man."

From flee@stanford.edu Sat Dec 09 20:15:36 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!stanford!flee
From: flee@stanford.edu (Fiona Lee)
Newsgroups: comp.dsp
Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Dec09.201536.6131@stanford.edu>
Date: Sat, 09 Dec 1995 20:15:36 GMT
References: <1995Dec07.212936.7569@hanse.de> <1995Dec09.104336.7967@unam.mx>
Organization: Stanford University Computer Systems Lab
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In article <1995Dec09.104336.7967@unam.mx>, elindqvist@unam.mx (Élodie 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.

-- 
Fiona Lee
Tape trading list upon request. SASE required for international mail.

From mtanaka@pipeline.com Mon Dec 11 18:28:36 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!pipeline!mtanaka
From: mtanaka@pipeline.com (Morag Tanaka)
Newsgroups: comp.dsp
Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Dec11.182836.4667@pipeline.com>
Date: Mon, 11 Dec 1995 18:28:36 GMT
References: <1995Dec07.212936.7569@hanse.de> <1995Dec09.104336.7967@unam.mx> <1995Dec09.201536.6131@stanford.edu>
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In article <1995Dec09.201536.6131@stanford.edu>, flee@stanford.edu (Fiona Lee) writes:
> Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in.

Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete.

-- 
Morag Tanaka
Opinions expressed are solely my own and not those of The Pipeline Internet Network.
------------------------------------------------------------

From fnovak@tum.de Tue Dec 12 12:17:36 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!tum!fnovak
From: fnovak@tum.de (Fiona Novak)
Newsgroups: comp.dsp
Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Dec12.121736.8387@tum.de>
Date: Tue, 12 Dec 1995 12:17:36 GMT
References: <1995Dec07.212936.7569@hanse.de> <1995Dec09.104336.7967@unam.mx> <1995Dec09.201536.6131@stanford.edu>
Organization: Technische Universität München
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In article <1995Dec09.201536.6131@stanford.edu>, flee@stanford.edu (Fiona Lee) writes:
> Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in.

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

-- 
Fiona Novak -- Technische Universität München
"Do not worship the copy."