From slopez@utexas.edu Fri Jun 02 00:14:52 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!utexas!slopez From: slopez@utexas.edu (Steve López) Newsgroups: comp.dsp Subject: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun02.001452.2718@utexas.edu> Date: Fri, 02 Jun 1995 00:14:52 GMT Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: WinVN 0.99.5 Lines: 11 Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. This leaves over 95% of the DSP56001's 16.5 MIPS available for other audio tasks. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Steve López US Robotics Courier V.34 @ 28,800 bps "We don't sign stars. We build them." From adubois@panix.com Fri Jun 02 11:16:52 1995 Path: ashpoly!cascade!mxgate!coyoacan!panix!adubois From: adubois@panix.com (Anja Dubois) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun02.111652.5863@panix.com> Date: Fri, 02 Jun 1995 11:16:52 GMT References: <1995Jun02.001452.2718@utexas.edu> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1995Jun02.001452.2718@utexas.edu>, slopez@utexas.edu (Steve López) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. > The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Anja Dubois *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0 From ydubois@utexas.edu Sat Jun 03 16:00:52 1995 Path: ashpoly!cascade!transat!ukc!fennimore!utexas!ydubois From: ydubois@utexas.edu (Yuki Dubois) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun03.160052.9644@utexas.edu> Date: Sat, 03 Jun 1995 16:00:52 GMT References: <1995Jun02.001452.2718@utexas.edu> <1995Jun02.111652.5863@panix.com> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Jun02.111652.5863@panix.com>, adubois@panix.com (Anja Dubois) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. > Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- === Yuki Dubois === Dept of Electrical Engineering, University of Texas at Austin "We don't sign stars. We build them." From skarlsson@mit.edu Mon Jun 05 05:17:52 1995 Path: ashpoly!cascade!bigsur!mit!skarlsson From: skarlsson@mit.edu (Seo-yeon Karlsson) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Jun05.051752.4051@mit.edu> Date: Mon, 05 Jun 1995 05:17:52 GMT References: <1995Jun02.001452.2718@utexas.edu> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Jun02.001452.2718@utexas.edu>, slopez@utexas.edu (Steve López) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Seo-yeon Karlsson "Tape doesn't lie at 02:14. Ears do." 486DX4/100 (FreeBSD 2.0.5) / FreeBSD 2.1