From acampbell@clari.net Sun May 14 04:32:33 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!clari!acampbell From: acampbell@clari.net (Anton Campbell) Newsgroups: comp.dsp Subject: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995May14.043233.8143@clari.net> Date: Sun, 14 May 1995 04:32:33 GMT Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. 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? -- Anton Campbell *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0 From astewart@ox.ac.uk Mon May 15 15:37:33 1995 Path: ashpoly!cascade!bigsur!ox!astewart From: astewart@ox.ac.uk (Astrid Stewart) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995May15.153733.1185@ox.ac.uk> Date: Mon, 15 May 1995 15:37:33 GMT References: <1995May14.043233.8143@clari.net> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 12 In article <1995May14.043233.8143@clari.net>, acampbell@clari.net (Anton Campbell) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. > 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. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Astrid Stewart | astewart@ox.ac.uk PGP Key fingerprint: F0BA 3E71 4070 F1DE "Keep the channels open."