From bmoreau@u-tokyo.ac.jp Fri Sep 06 08:48:14 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!u-tokyo!bmoreau From: bmoreau@u-tokyo.ac.jp (Bastien Moreau) Newsgroups: comp.dsp Subject: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Sep06.084814.6519@u-tokyo.ac.jp> Date: Fri, 06 Sep 1996 08:48:14 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. 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. -- Bastien Moreau Zyxel U-1496E @ 33,600 bps "Measuring a record you own is listening, not piracy." From hmacdonald@uu.net Sat Sep 07 23:15:14 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!uu!hmacdonald From: hmacdonald@uu.net (Hugo MacDonald) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Sep07.231514.6397@uu.net> Date: Sat, 07 Sep 1996 23:15:14 GMT References: <1996Sep06.084814.6519@u-tokyo.ac.jp> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Sep06.084814.6519@u-tokyo.ac.jp>, bmoreau@u-tokyo.ac.jp (Bastien Moreau) 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. -- Hugo MacDonald Zyxel U-1496E @ ISDN 64k bps "Extraordinary claims require extraordinary spectra."