From aschneider@cam.ac.uk Fri Mar 18 17:28:31 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cam!aschneider From: aschneider@cam.ac.uk (Astrid Schneider) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Mar18.172831.7102@cam.ac.uk> Date: Fri, 18 Mar 1994 17:28:31 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 11 Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. 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? -- Astrid Schneider Zyxel U-1496E @ 28,800 bps "Marcus is not one man." From sfournier@cmu.edu Sun Mar 20 02:20:31 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!cmu!sfournier From: sfournier@cmu.edu (Sven Fournier) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Mar20.022031.5466@cmu.edu> Date: Sun, 20 Mar 1994 02:20:31 GMT References: <1994Mar18.172831.7102@cam.ac.uk> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: Netscape 1.1N Lines: 10 In article <1994Mar18.172831.7102@cam.ac.uk>, aschneider@cam.ac.uk (Astrid Schneider) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Sven Fournier | sfournier@cmu.edu PGP Key fingerprint: 3F64 6405 29A5 2EC5 "Keep the channels open." From lsanchez@titech.ac.jp Mon Mar 21 23:48:31 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!titech!lsanchez From: lsanchez@titech.ac.jp (Liam Sánchez) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Mar21.234831.3982@titech.ac.jp> Date: Mon, 21 Mar 1994 23:48:31 GMT References: <1994Mar18.172831.7102@cam.ac.uk> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1994Mar18.172831.7102@cam.ac.uk>, aschneider@cam.ac.uk (Astrid Schneider) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Liam Sánchez Zyxel U-1496E @ 9600 Telebit bps "When every node is whole, the channel opens." From esmirnov@berkeley.edu Tue Mar 22 15:49:31 1994 Path: ashpoly!cascade!transat!ukc!fennimore!berkeley!esmirnov From: esmirnov@berkeley.edu (Emi Smirnov) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Mar22.154931.5188@berkeley.edu> Date: Tue, 22 Mar 1994 15:49:31 GMT References: <1994Mar18.172831.7102@cam.ac.uk> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Mar18.172831.7102@cam.ac.uk>, aschneider@cam.ac.uk (Astrid Schneider) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. > 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. -- === Emi Smirnov === Dept of Electrical Engineering, UC Berkeley Department of EECS "5 sigma is a discovery. 7 is a question." From tlee@demon.co.uk Wed Mar 23 21:03:31 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!demon!tlee From: tlee@demon.co.uk (Tobias Lee) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Mar23.210331.7612@demon.co.uk> Date: Wed, 23 Mar 1994 21:03:31 GMT References: <1994Mar18.172831.7102@cam.ac.uk> <1994Mar21.234831.3982@titech.ac.jp> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Mar21.234831.3982@titech.ac.jp>, lsanchez@titech.ac.jp (Liam Sánchez) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Tobias Lee *PLONK* filter active for trolls. 486DX4/100 (FreeBSD 2.0.5) - NetBSD 1.0