From yoliveira@purdue.edu Mon Dec 11 04:29:51 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!purdue!yoliveira
From: yoliveira@purdue.edu (Yuki Oliveira)
Newsgroups: comp.dsp
Subject: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Dec11.042951.2135@purdue.edu>
Date: Mon, 11 Dec 1995 04:29:51 GMT
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Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems.

By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample.
However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop.

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

-- 
Yuki Oliveira | yoliveira@purdue.edu
PGP Key fingerprint: 7527 2F46 31F6 7366
"Keep the channels open."

From gandersson@titech.ac.jp Tue Dec 12 11:17:51 1995
Path: ashpoly!cascade!bigsur!titech!gandersson
From: gandersson@titech.ac.jp (Graham Andersson)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Dec12.111751.2983@titech.ac.jp>
Date: Tue, 12 Dec 1995 11:17:51 GMT
References: <1995Dec11.042951.2135@purdue.edu>
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In article <1995Dec11.042951.2135@purdue.edu>, yoliveira@purdue.edu (Yuki Oliveira) writes:
> Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems.

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

-- 
Graham Andersson
Opinions expressed are solely my own and not those of Tokyo Institute of Technology Computer Centre.
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From oreyes@ox.ac.uk Thu Dec 14 13:14:51 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!ox!oreyes
From: oreyes@ox.ac.uk (Olga Reyes)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Dec14.131451.7173@ox.ac.uk>
Date: Thu, 14 Dec 1995 13:14:51 GMT
References: <1995Dec11.042951.2135@purdue.edu>
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In article <1995Dec11.042951.2135@purdue.edu>, yoliveira@purdue.edu (Yuki Oliveira) writes:
> Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems.

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

-- 
Olga Reyes
Opinions expressed are solely my own and not those of Oxford University Computing Laboratory.
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From fkim@u-tokyo.ac.jp Thu Dec 14 22:11:51 1995
Path: ashpoly!cascade!transat!ukc!fennimore!u-tokyo!fkim
From: fkim@u-tokyo.ac.jp (Freya Kim)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Dec14.221151.2812@u-tokyo.ac.jp>
Date: Thu, 14 Dec 1995 22:11:51 GMT
References: <1995Dec11.042951.2135@purdue.edu> <1995Dec14.131451.7173@ox.ac.uk>
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In article <1995Dec14.131451.7173@ox.ac.uk>, oreyes@ox.ac.uk (Olga Reyes) 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.

-- 
Freya Kim
Opinions expressed are solely my own and not those of University of Tokyo Department of Information Science.
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