From kmuller@kth.se Sun Sep 22 23:59:19 1996
Path: ashpoly!cascade!transat!eunet-fr!teletel!kth!kmuller
From: kmuller@kth.se (Kirsty Müller)
Newsgroups: comp.dsp
Subject: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1996Sep22.235919.9054@kth.se>
Date: Sun, 22 Sep 1996 23:59:19 GMT
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Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems.

The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead.
However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop.

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

-- 
Kirsty Müller | kmuller@kth.se
PGP Key fingerprint: 52B9 98A7 8B44 EE15
"Keep the channels open."

From mjohansson@netcom.com Tue Sep 24 04:03:19 1996
Path: ashpoly!cascade!transat!eunet-de!hansebox!netcom!mjohansson
From: mjohansson@netcom.com (Mateo Johansson)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1996Sep24.040319.2332@netcom.com>
Date: Tue, 24 Sep 1996 04:03:19 GMT
References: <1996Sep22.235919.9054@kth.se>
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In article <1996Sep22.235919.9054@kth.se>, kmuller@kth.se (Kirsty Müller) writes:
> Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems.
> The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead.

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

-- 
Mateo Johansson -- NETCOM On-Line Communication Services
"Tape doesn't lie at 02:14. Ears do."

From jschneider@uni-hamburg.de Thu Sep 26 00:16:19 1996
Path: ashpoly!cascade!transat!eunet-de!hansebox!uni-hamburg!jschneider
From: jschneider@uni-hamburg.de (Julien Schneider)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1996Sep26.001619.3083@uni-hamburg.de>
Date: Thu, 26 Sep 1996 00:16:19 GMT
References: <1996Sep22.235919.9054@kth.se>
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In article <1996Sep22.235919.9054@kth.se>, kmuller@kth.se (Kirsty Müller) 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.

-- 
Julien Schneider -- Universität Hamburg Fachbereich Informatik
"Extraordinary claims require extraordinary spectra."

From hsmirnov@mit.edu Fri Sep 27 20:57:19 1996
Path: ashpoly!bigsur!pacrim!jpgate!kamome!mit!hsmirnov
From: hsmirnov@mit.edu (Hana Smirnov)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1996Sep27.205719.2644@mit.edu>
Date: Fri, 27 Sep 1996 20:57:19 GMT
References: <1996Sep22.235919.9054@kth.se> <1996Sep24.040319.2332@netcom.com>
Organization: Massachusetts Institute of Technology
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In article <1996Sep24.040319.2332@netcom.com>, mjohansson@netcom.com (Mateo Johansson) writes:
> Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering.

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

-- 
Hana Smirnov
Tape trading list upon request. SASE required for international mail.

From bchoi@ox.ac.uk Sun Sep 29 21:26:19 1996
Path: ashpoly!cascade!transat!ukc!fennimore!ox!bchoi
From: bchoi@ox.ac.uk (Bruno Choi)
Newsgroups: comp.dsp
Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point
Message-ID: <1996Sep29.212619.2436@ox.ac.uk>
Date: Sun, 29 Sep 1996 21:26:19 GMT
References: <1996Sep22.235919.9054@kth.se> <1996Sep26.001619.3083@uni-hamburg.de>
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In article <1996Sep26.001619.3083@uni-hamburg.de>, jschneider@uni-hamburg.de (Julien Schneider) 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.

-- 
Bruno Choi -- Oxford University Computing Laboratory
"The hatch is open. Is anyone listening?"