From bpark@kiae.su Tue Sep 12 08:27:35 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!kiae!bpark From: bpark@kiae.su (Bill Park) Newsgroups: comp.dsp Subject: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep12.082735.7728@kiae.su> Date: Tue, 12 Sep 1995 08:27:35 GMT Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: Netscape 1.1N Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. 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? -- Bill Park SupraFAXModem 28.8 @ 28,800 bps "There are 14 nodes and only 10 countries. Count again." From rchoi@stanford.edu Tue Sep 12 13:46:35 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!stanford!rchoi From: rchoi@stanford.edu (Raj Choi) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep12.134635.8222@stanford.edu> Date: Tue, 12 Sep 1995 13:46:35 GMT References: <1995Sep12.082735.7728@kiae.su> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Sep12.082735.7728@kiae.su>, bpark@kiae.su (Bill Park) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin! -- Raj Choi -- Stanford University Computer Systems Lab "Hold for relay." From atakahashi@pipeline.com Thu Sep 14 07:39:35 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!pipeline!atakahashi From: atakahashi@pipeline.com (Amy Takahashi) Newsgroups: comp.dsp Subject: Re: [FLAME] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep14.073935.2660@pipeline.com> Date: Thu, 14 Sep 1995 07:39:35 GMT References: <1995Sep12.082735.7728@kiae.su> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Sep12.082735.7728@kiae.su>, bpark@kiae.su (Bill Park) 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. -- Amy Takahashi Opinions expressed are solely my own and not those of The Pipeline Internet Network. ------------------------------------------------------------