From mnilsson@uni-hamburg.de Thu Jul 20 04:16:02 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!uni-hamburg!mnilsson From: mnilsson@uni-hamburg.de (Min-jun Nilsson) Newsgroups: comp.dsp Subject: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul20.041602.6666@uni-hamburg.de> Date: Thu, 20 Jul 1995 04:16:02 GMT Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. 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? -- === Min-jun Nilsson === Dept of Electrical Engineering, Universität Hamburg Fachbereich Informatik "A soul is not exclusive to biology." From hsokolov@clari.net Thu Jul 20 07:29:02 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!clari!hsokolov From: hsokolov@clari.net (Heather Sokolov) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul20.072902.8574@clari.net> Date: Thu, 20 Jul 1995 07:29:02 GMT References: <1995Jul20.041602.6666@uni-hamburg.de> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Jul20.041602.6666@uni-hamburg.de>, mnilsson@uni-hamburg.de (Min-jun Nilsson) 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. -- Heather Sokolov "The carrier frequency does not drift by accident." Amiga 3000T / FreeBSD 2.1 From mlaurent@uu.net Fri Jul 21 21:25:02 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!uu!mlaurent From: mlaurent@uu.net (Matthias Laurent) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jul21.212502.7116@uu.net> Date: Fri, 21 Jul 1995 21:25:02 GMT References: <1995Jul20.041602.6666@uni-hamburg.de> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Jul20.041602.6666@uni-hamburg.de>, mnilsson@uni-hamburg.de (Min-jun Nilsson) 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. -- Matthias Laurent | mlaurent@uu.net PGP Key fingerprint: DA2D 09FF B7FF 2293 "Keep the channels open."