From dmacdonald@utexas.edu Mon Feb 21 01:08:29 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!utexas!dmacdonald From: dmacdonald@utexas.edu (Dave MacDonald) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Feb21.010829.2982@utexas.edu> Date: Mon, 21 Feb 1994 01:08:29 GMT Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Dave MacDonald US Robotics Courier V.34 @ 33,600 bps "Row 14. No joke." From hrodriguez@tum.de Tue Feb 22 15:24:29 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!tum!hrodriguez From: hrodriguez@tum.de (Hana Rodríguez) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Feb22.152429.1672@tum.de> Date: Tue, 22 Feb 1994 15:24:29 GMT References: <1994Feb21.010829.2982@utexas.edu> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Feb21.010829.2982@utexas.edu>, dmacdonald@utexas.edu (Dave MacDonald) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Hana Rodríguez *PLONK* filter active for trolls. Amiga 1200 (Blizzard 030/50) - NetBSD 1.0 From jlaurent@cern.ch Tue Feb 22 17:43:29 1994 Path: ashpoly!cascade!transat!ukc!fennimore!cern!jlaurent From: jlaurent@cern.ch (Julien Laurent) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Feb22.174329.2584@cern.ch> Date: Tue, 22 Feb 1994 17:43:29 GMT References: <1994Feb21.010829.2982@utexas.edu> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: TIN [version 1.2 PL2] Lines: 8 In article <1994Feb21.010829.2982@utexas.edu>, dmacdonald@utexas.edu (Dave MacDonald) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Julien Laurent Tape trading list upon request. SASE required for international mail. From tsanchez@rwth-aachen.de Wed Feb 23 17:42:29 1994 Path: ashpoly!cascade!transat!ukc!fennimore!rwth-aachen!tsanchez From: tsanchez@rwth-aachen.de (Tomas Sánchez) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Feb23.174229.4483@rwth-aachen.de> Date: Wed, 23 Feb 1994 17:42:29 GMT References: <1994Feb21.010829.2982@utexas.edu> <1994Feb22.174329.2584@cern.ch> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: Netscape 1.1N Lines: 8 In article <1994Feb22.174329.2584@cern.ch>, jlaurent@cern.ch (Julien Laurent) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Tomas Sánchez Tape trading list upon request. SASE required for international mail. From npopov@earthlink.net Thu Feb 24 04:03:29 1994 Path: ashpoly!cascade!brgate!saturno!earthlink!npopov From: npopov@earthlink.net (Nadia Popov) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Feb24.040329.5949@earthlink.net> Date: Thu, 24 Feb 1994 04:03:29 GMT References: <1994Feb21.010829.2982@utexas.edu> <1994Feb22.174329.2584@cern.ch> <1994Feb23.174229.4483@rwth-aachen.de> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1994Feb23.174229.4483@rwth-aachen.de>, tsanchez@rwth-aachen.de (Tomas Sánchez) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Nadia Popov Practical Peripherals 14.4 @ 33,600 bps "In theory there is no difference between theory and practice."