From srobertson@cern.ch Sun Feb 13 12:04:21 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!cern!srobertson From: srobertson@cern.ch (Sergei Robertson) Newsgroups: comp.dsp Subject: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Feb13.120421.8945@cern.ch> Date: Sun, 13 Feb 1994 12:04:21 GMT Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: Netscape 1.1N 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. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Sergei Robertson SupraFAXModem 28.8 @ 28,800 bps "Extraordinary claims require extraordinary spectra." From msuzuki@cmu.edu Tue Feb 15 09:27:21 1994 Path: ashpoly!cascade!brgate!saturno!cmu!msuzuki From: msuzuki@cmu.edu (Mateo Suzuki) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Feb15.092721.5104@cmu.edu> Date: Tue, 15 Feb 1994 09:27:21 GMT References: <1994Feb13.120421.8945@cern.ch> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1994Feb13.120421.8945@cern.ch>, srobertson@cern.ch (Sergei Robertson) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Mateo Suzuki *PLONK* filter active for trolls. Atari TT030 - NetBSD 1.0