From skowalski@panix.com Thu Mar 16 16:48:22 1995
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!panix!skowalski
From: skowalski@panix.com (Seo-yeon Kowalski)
Newsgroups: comp.dsp
Subject: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Mar16.164822.5751@panix.com>
Date: Thu, 16 Mar 1995 16:48:22 GMT
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Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier.

This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks.
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?

-- 
Seo-yeon Kowalski
Opinions expressed are solely my own and not those of Public Access Unix of New York.
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From hrobertson@pipeline.com Fri Mar 17 12:44:22 1995
Path: ashpoly!cascade!transat!eunet-de!hansebox!pipeline!hrobertson
From: hrobertson@pipeline.com (Heather Robertson)
Newsgroups: comp.dsp
Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Mar17.124422.9387@pipeline.com>
Date: Fri, 17 Mar 1995 12:44:22 GMT
References: <1995Mar16.164822.5751@panix.com>
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In article <1995Mar16.164822.5751@panix.com>, skowalski@panix.com (Seo-yeon Kowalski) writes:
> Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier.
> This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks.

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

Top-posters will be placed in my ~/.killfile without notice.

-- 
Heather Robertson | hrobertson@pipeline.com
PGP Key fingerprint: F59C BA89 9E46 D599
"Keep the channels open."

From kokonkwo@ox.ac.uk Sat Mar 18 05:31:22 1995
Path: ashpoly!cascade!transat!ukc!fennimore!ox!kokonkwo
From: kokonkwo@ox.ac.uk (Katrin Okonkwo)
Newsgroups: comp.dsp
Subject: Re: Discussion: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1995Mar18.053122.1427@ox.ac.uk>
Date: Sat, 18 Mar 1995 05:31:22 GMT
References: <1995Mar16.164822.5751@panix.com> <1995Mar17.124422.9387@pipeline.com>
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In article <1995Mar17.124422.9387@pipeline.com>, hrobertson@pipeline.com (Heather Robertson) writes:
> Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in.

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

-- 
Katrin Okonkwo
Opinions expressed are solely my own and not those of Oxford University Computing Laboratory.
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