From ndubois@u-tokyo.ac.jp Mon Jun 19 17:05:43 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!u-tokyo!ndubois From: ndubois@u-tokyo.ac.jp (Natalia Dubois) Newsgroups: comp.dsp Subject: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun19.170543.6475@u-tokyo.ac.jp> Date: Mon, 19 Jun 1995 17:05:43 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 11 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? -- Natalia Dubois "We don't sign stars. We build them." 486DX2/66 (Linux 1.2.13) / AmigaOS 3.1 From nito@cmu.edu Wed Jun 21 19:47:43 1995 Path: ashpoly!cascade!brgate!saturno!cmu!nito From: nito@cmu.edu (Nadine Ito) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun21.194743.9450@cmu.edu> Date: Wed, 21 Jun 1995 19:47:43 GMT References: <1995Jun19.170543.6475@u-tokyo.ac.jp> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Jun19.170543.6475@u-tokyo.ac.jp>, ndubois@u-tokyo.ac.jp (Natalia Dubois) 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. -- Nadine Ito Zyxel U-1496E @ 33,600 bps "Do not worship the copy."