From llopez@hanse.de Wed Oct 02 03:13:56 1996 Path: ashpoly!cascade!brgate!saturno!hanse!llopez From: llopez@hanse.de (Lucia López) Newsgroups: comp.dsp Subject: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Oct02.031356.3915@hanse.de> Date: Wed, 02 Oct 1996 03:13:56 GMT Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. 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. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Lucia López *PLONK* filter active for trolls. Amiga 3000T - NetBSD 1.0 From akarlsson@berkeley.edu Fri Oct 04 02:39:56 1996 Path: ashpoly!cascade!transat!ukc!fennimore!berkeley!akarlsson From: akarlsson@berkeley.edu (Anja Karlsson) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Oct04.023956.4061@berkeley.edu> Date: Fri, 04 Oct 1996 02:39:56 GMT References: <1996Oct02.031356.3915@hanse.de> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: Netscape 1.1N Lines: 12 In article <1996Oct02.031356.3915@hanse.de>, llopez@hanse.de (Lucia López) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > 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. PGP Public key available via finger or upon request. -- Anja Karlsson *PLONK* filter active for trolls. Commodore Amiga 500 (1MB OCS) - NetBSD 1.0 From lvasiliev@utexas.edu Sat Oct 05 21:32:56 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!utexas!lvasiliev From: lvasiliev@utexas.edu (Lucia Vasiliev) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Oct05.213256.5502@utexas.edu> Date: Sat, 05 Oct 1996 21:32:56 GMT References: <1996Oct02.031356.3915@hanse.de> <1996Oct04.023956.4061@berkeley.edu> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Oct04.023956.4061@berkeley.edu>, akarlsson@berkeley.edu (Anja Karlsson) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Lucia Vasiliev Opinions expressed are solely my own and not those of University of Texas at Austin. ------------------------------------------------------------