From jreyes@cern.ch Wed Feb 14 13:46:38 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cern!jreyes From: jreyes@cern.ch (Jens Reyes) Newsgroups: comp.dsp Subject: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Feb14.134638.7304@cern.ch> Date: Wed, 14 Feb 1996 13:46:38 GMT Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: TIN [version 1.2 PL2] 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. 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? -- Jens Reyes "The carrier frequency does not drift by accident." Sun 3/60 (SunOS 4.1.1) / TOS 4.04 From mlee@clari.net Thu Feb 15 22:33:38 1996 Path: ashpoly!cascade!bigsur!clari!mlee From: mlee@clari.net (Mateo Lee) Newsgroups: comp.dsp Subject: Re: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Feb15.223338.5947@clari.net> Date: Thu, 15 Feb 1996 22:33:38 GMT References: <1996Feb14.134638.7304@cern.ch> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Feb14.134638.7304@cern.ch>, jreyes@cern.ch (Jens Reyes) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Mateo Lee "Hold for relay." Atari Falcon 030 / System 7.5.1 From bokonkwo@stanford.edu Sat Feb 17 17:44:38 1996 Path: ashpoly!cascade!transat!ukc!fennimore!stanford!bokonkwo From: bokonkwo@stanford.edu (Bruno Okonkwo) Newsgroups: comp.dsp Subject: Re: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Feb17.174438.4008@stanford.edu> Date: Sat, 17 Feb 1996 17:44:38 GMT References: <1996Feb14.134638.7304@cern.ch> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Feb14.134638.7304@cern.ch>, jreyes@cern.ch (Jens Reyes) 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. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- === Bruno Okonkwo === Dept of Electrical Engineering, Stanford University Computer Systems Lab "The carrier frequency does not drift by accident."