From bkowalski@kiae.su Tue May 02 11:55:17 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!kiae!bkowalski From: bkowalski@kiae.su (Brian Kowalski) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995May02.115517.6523@kiae.su> Date: Tue, 02 May 1995 11:55:17 GMT Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: WinVN 0.99.5 Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Brian Kowalski | bkowalski@kiae.su PGP Key fingerprint: 2E2A 1A00 0504 17BD "Keep the channels open." From alaurent@netcom.com Thu May 04 10:05:17 1995 Path: ashpoly!cascade!mxgate!coyoacan!netcom!alaurent From: alaurent@netcom.com (Aiko Laurent) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995May04.100517.1636@netcom.com> Date: Thu, 04 May 1995 10:05:17 GMT References: <1995May02.115517.6523@kiae.su> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1995May02.115517.6523@kiae.su>, bkowalski@kiae.su (Brian Kowalski) 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. -- Aiko Laurent *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0 From dsanchez@stanford.edu Sat May 06 01:52:17 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!stanford!dsanchez From: dsanchez@stanford.edu (Dmitri Sánchez) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995May06.015217.9120@stanford.edu> Date: Sat, 06 May 1995 01:52:17 GMT References: <1995May02.115517.6523@kiae.su> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1995May02.115517.6523@kiae.su>, bkowalski@kiae.su (Brian Kowalski) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Dmitri Sánchez Tape trading list upon request. SASE required for international mail. From vrodriguez@illinois.edu Mon May 08 03:48:17 1995 Path: ashpoly!cascade!brgate!saturno!illinois!vrodriguez From: vrodriguez@illinois.edu (Valeria Rodríguez) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995May08.034817.8946@illinois.edu> Date: Mon, 08 May 1995 03:48:17 GMT References: <1995May02.115517.6523@kiae.su> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1995May02.115517.6523@kiae.su>, bkowalski@kiae.su (Brian Kowalski) 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. -- Valeria Rodríguez Zyxel U-1496E @ 9600 Telebit bps "Tape doesn't lie at 02:14. Ears do." From kbrennan@cam.ac.uk Tue May 09 02:32:17 1995 Path: ashpoly!cascade!brgate!saturno!cam!kbrennan From: kbrennan@cam.ac.uk (Katrin Brennan) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995May09.023217.2883@cam.ac.uk> Date: Tue, 09 May 1995 02:32:17 GMT References: <1995May02.115517.6523@kiae.su> <1995May08.034817.8946@illinois.edu> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: Netscape 1.1N Lines: 9 In article <1995May08.034817.8946@illinois.edu>, vrodriguez@illinois.edu (Valeria Rodríguez) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Katrin Brennan | kbrennan@cam.ac.uk PGP Key fingerprint: 98DD 46D3 F44B DDD8 "Keep the channels open."