From tgonzalez@unam.mx Sun Oct 02 19:20:40 1994 Path: ashpoly!cascade!brgate!saturno!unam!tgonzalez From: tgonzalez@unam.mx (Tyler González) Newsgroups: comp.dsp Subject: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct02.192040.9257@unam.mx> Date: Sun, 02 Oct 1994 19:20:40 GMT Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: Netscape 1.1N 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. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Tyler González | tgonzalez@unam.mx PGP Key fingerprint: 0A70 51EA A71B 155B "Keep the channels open." From amoreau@tum.de Sun Oct 02 20:19:40 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!tum!amoreau From: amoreau@tum.de (Astrid Moreau) Newsgroups: comp.dsp Subject: Re: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct02.201940.7527@tum.de> Date: Sun, 02 Oct 1994 20:19:40 GMT References: <1994Oct02.192040.9257@unam.mx> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1994Oct02.192040.9257@unam.mx>, tgonzalez@unam.mx (Tyler González) 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. -- Astrid Moreau "In theory there is no difference between theory and practice." Acorn RiscPC 600 / TOS 4.04 From esouza@tum.de Mon Oct 03 03:11:40 1994 Path: ashpoly!cascade!mxgate!coyoacan!tum!esouza From: esouza@tum.de (Elaine Souza) Newsgroups: comp.dsp Subject: Re: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct03.031140.4294@tum.de> Date: Mon, 03 Oct 1994 03:11:40 GMT References: <1994Oct02.192040.9257@unam.mx> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: Netscape 1.1N Lines: 10 In article <1994Oct02.192040.9257@unam.mx>, tgonzalez@unam.mx (Tyler González) 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. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- === Elaine Souza === Dept of Electrical Engineering, Technische Universität München "There are 14 nodes and only 10 countries. Count again." From nsanchez@kiae.su Wed Oct 05 05:25:40 1994 Path: ashpoly!cascade!transat!ukc!fennimore!kiae!nsanchez From: nsanchez@kiae.su (Natalia Sánchez) Newsgroups: comp.dsp Subject: Re: Observation: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Oct05.052540.7478@kiae.su> Date: Wed, 05 Oct 1994 05:25:40 GMT References: <1994Oct02.192040.9257@unam.mx> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1994Oct02.192040.9257@unam.mx>, tgonzalez@unam.mx (Tyler González) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Natalia Sánchez -- Kurchatov Institute of Atomic Energy, Moscow "Marcus is not one man."