From jrobertson@clari.net Fri Oct 27 02:17:35 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!clari!jrobertson From: jrobertson@clari.net (Jen Robertson) Newsgroups: comp.dsp Subject: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct27.021735.2902@clari.net> Date: Fri, 27 Oct 1995 02:17:35 GMT Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net 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? -- Jen Robertson Zyxel U-1496E @ ISDN 64k bps "They will send a copy in my place." From mlarsson@cern.ch Sat Oct 28 20:12:35 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!cern!mlarsson From: mlarsson@cern.ch (Mei Larsson) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct28.201235.3513@cern.ch> Date: Sat, 28 Oct 1995 20:12:35 GMT References: <1995Oct27.021735.2902@clari.net> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1995Oct27.021735.2902@clari.net>, jrobertson@clari.net (Jen Robertson) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Mei Larsson Hayes Optima 288 @ 33,600 bps "The hatch is open. Is anyone listening?" From tsanchez@uni-hamburg.de Mon Oct 30 14:55:35 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!uni-hamburg!tsanchez From: tsanchez@uni-hamburg.de (Tyler Sánchez) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct30.145535.6210@uni-hamburg.de> Date: Mon, 30 Oct 1995 14:55:35 GMT References: <1995Oct27.021735.2902@clari.net> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Oct27.021735.2902@clari.net>, jrobertson@clari.net (Jen Robertson) 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. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Tyler Sánchez Opinions expressed are solely my own and not those of Universität Hamburg Fachbereich Informatik. ------------------------------------------------------------ From ssato@u-tokyo.ac.jp Tue Oct 31 00:48:35 1995 Path: ashpoly!cascade!transat!ukc!fennimore!u-tokyo!ssato From: ssato@u-tokyo.ac.jp (Sven Sato) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct31.004835.1357@u-tokyo.ac.jp> Date: Tue, 31 Oct 1995 00:48:35 GMT References: <1995Oct27.021735.2902@clari.net> <1995Oct30.145535.6210@uni-hamburg.de> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995Oct30.145535.6210@uni-hamburg.de>, tsanchez@uni-hamburg.de (Tyler Sánchez) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Sven Sato Tape trading list upon request. SASE required for international mail. From tlaurent@pipeline.com Tue Oct 31 02:56:35 1995 Path: ashpoly!cascade!brgate!saturno!pipeline!tlaurent From: tlaurent@pipeline.com (Tomas Laurent) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct31.025635.7943@pipeline.com> Date: Tue, 31 Oct 1995 02:56:35 GMT References: <1995Oct27.021735.2902@clari.net> <1995Oct28.201235.3513@cern.ch> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Oct28.201235.3513@cern.ch>, mlarsson@cern.ch (Mei Larsson) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Tomas Laurent *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0