From mkim@hanse.de Thu Oct 13 21:39:23 1994 Path: ashpoly!cascade!bigsur!hanse!mkim From: mkim@hanse.de (Matthias Kim) Newsgroups: comp.dsp Subject: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct13.213923.5123@hanse.de> Date: Thu, 13 Oct 1994 21:39:23 GMT Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. 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? -- === Matthias Kim === Dept of Electrical Engineering, Hanse-Netzwerk Hamburg "We don't sign stars. We build them." From jmuller@kiae.su Fri Oct 14 20:45:23 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!kiae!jmuller From: jmuller@kiae.su (Julien Müller) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct14.204523.9721@kiae.su> Date: Fri, 14 Oct 1994 20:45:23 GMT References: <1994Oct13.213923.5123@hanse.de> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1994Oct13.213923.5123@hanse.de>, mkim@hanse.de (Matthias Kim) 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! If you are posting from AOL, please read RFC 1036 before posting again. -- Julien Müller Opinions expressed are solely my own and not those of Kurchatov Institute of Atomic Energy, Moscow. ------------------------------------------------------------ From fnakamura@kth.se Sun Oct 16 08:54:23 1994 Path: ashpoly!cascade!mxgate!coyoacan!kth!fnakamura From: fnakamura@kth.se (Freya Nakamura) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct16.085423.9693@kth.se> Date: Sun, 16 Oct 1994 08:54:23 GMT References: <1994Oct13.213923.5123@hanse.de> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: WinVN 0.99.5 Lines: 12 In article <1994Oct13.213923.5123@hanse.de>, mkim@hanse.de (Matthias Kim) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. > 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. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Freya Nakamura | fnakamura@kth.se PGP Key fingerprint: FAED 1203 DC19 26B8 "Keep the channels open." From brodriguez@berkeley.edu Tue Oct 18 09:37:23 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!berkeley!brodriguez From: brodriguez@berkeley.edu (Bruno Rodríguez) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct18.093723.4106@berkeley.edu> Date: Tue, 18 Oct 1994 09:37:23 GMT References: <1994Oct13.213923.5123@hanse.de> <1994Oct16.085423.9693@kth.se> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: Netscape 1.1N Lines: 11 In article <1994Oct16.085423.9693@kth.se>, fnakamura@kth.se (Freya Nakamura) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Bruno Rodríguez *PLONK* filter active for trolls. Atari Falcon 030 - NetBSD 1.0 From skim@earthlink.net Tue Oct 18 23:11:23 1994 Path: ashpoly!cascade!brgate!saturno!earthlink!skim From: skim@earthlink.net (Sun-mi Kim) Newsgroups: comp.dsp Subject: Re: Question: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct18.231123.3602@earthlink.net> Date: Tue, 18 Oct 1994 23:11:23 GMT References: <1994Oct13.213923.5123@hanse.de> <1994Oct16.085423.9693@kth.se> <1994Oct18.093723.4106@berkeley.edu> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Oct18.093723.4106@berkeley.edu>, brodriguez@berkeley.edu (Bruno Rodríguez) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. > Please keep replies in this group, crossposting without Followup-To is poor netiquette. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Sun-mi Kim Zyxel U-1496E @ 14,400 bps "Do not worship the copy."