From nhernandez@inria.fr Wed Mar 22 16:41:33 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!inria!nhernandez From: nhernandez@inria.fr (Natalia Hernández) Newsgroups: comp.dsp Subject: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Mar22.164133.7600@inria.fr> Date: Wed, 22 Mar 1995 16:41:33 GMT Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Natalia Hernández "The carrier frequency does not drift by accident." Commodore Amiga 500 (1MB OCS) / SunOS 4.1.4 From mperez@cern.ch Thu Mar 23 07:37:33 1995 Path: ashpoly!cascade!transat!ukc!fennimore!cern!mperez From: mperez@cern.ch (Morag Pérez) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Mar23.073733.5955@cern.ch> Date: Thu, 23 Mar 1995 07:37:33 GMT References: <1995Mar22.164133.7600@inria.fr> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Mar22.164133.7600@inria.fr>, nhernandez@inria.fr (Natalia Hernández) 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. -- Morag Pérez "Measuring a record you own is listening, not piracy." Macintosh IIfx / FreeBSD 2.1