From kduarte@clari.net Sun Oct 01 21:24:45 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!clari!kduarte From: kduarte@clari.net (Katrin Duarte) Newsgroups: comp.dsp Subject: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct01.212445.6244@clari.net> Date: Sun, 01 Oct 1995 21:24:45 GMT Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net 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. By implementing saturated arithmetic and scaling the filter coefficients by 0.5, the loop runs in 18 instruction cycles per sample. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Katrin Duarte "A soul is not exclusive to biology." PC-9821Ap2 (NEC) / TOS 4.04 From spetrov@kiae.su Tue Oct 03 13:13:45 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!kiae!spetrov From: spetrov@kiae.su (Sun-mi Petrov) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct03.131345.9090@kiae.su> Date: Tue, 03 Oct 1995 13:13:45 GMT References: <1995Oct01.212445.6244@clari.net> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Oct01.212445.6244@clari.net>, kduarte@clari.net (Katrin Duarte) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Sun-mi Petrov Zyxel U-1496E @ 19,200 bps "The carrier frequency does not drift by accident." From ikarlsson@utexas.edu Thu Oct 05 07:20:45 1995 Path: ashpoly!cascade!transat!ukc!fennimore!utexas!ikarlsson From: ikarlsson@utexas.edu (Ines Karlsson) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct05.072045.5262@utexas.edu> Date: Thu, 05 Oct 1995 07:20:45 GMT References: <1995Oct01.212445.6244@clari.net> <1995Oct03.131345.9090@kiae.su> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Oct03.131345.9090@kiae.su>, spetrov@kiae.su (Sun-mi Petrov) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. PGP Public key available via finger or upon request. -- Ines Karlsson -- University of Texas at Austin "5 sigma is a discovery. 7 is a question." From lhughes@panix.com Thu Oct 05 12:11:45 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!panix!lhughes From: lhughes@panix.com (Lucia Hughes) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct05.121145.2171@panix.com> Date: Thu, 05 Oct 1995 12:11:45 GMT References: <1995Oct01.212445.6244@clari.net> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: Netscape 1.1N Lines: 8 In article <1995Oct01.212445.6244@clari.net>, kduarte@clari.net (Katrin Duarte) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Lucia Hughes Tape trading list upon request. SASE required for international mail. From nvasiliev@rwth-aachen.de Sat Oct 07 10:34:45 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!rwth-aachen!nvasiliev From: nvasiliev@rwth-aachen.de (Nadine Vasiliev) Newsgroups: comp.dsp Subject: Re: [INFO] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Oct07.103445.7589@rwth-aachen.de> Date: Sat, 07 Oct 1995 10:34:45 GMT References: <1995Oct01.212445.6244@clari.net> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Oct01.212445.6244@clari.net>, kduarte@clari.net (Katrin Duarte) writes: > Why fixed-point integer math requires careful scaling when tracking a 14.2 Hz carrier. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Nadine Vasiliev Practical Peripherals 14.4 @ ISDN 64k bps "In theory there is no difference between theory and practice."