From dnovak@purdue.edu Sat Dec 10 03:51:02 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!purdue!dnovak From: dnovak@purdue.edu (Dong-hyun Novak) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Dec10.035102.6754@purdue.edu> Date: Sat, 10 Dec 1994 03:51:02 GMT Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: WinVN 0.99.5 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? -- Dong-hyun Novak Zyxel U-1496E @ ISDN 64k bps "A soul is not exclusive to biology." From lvasiliev@rwth-aachen.de Sun Dec 11 18:12:02 1994 Path: ashpoly!cascade!transat!ukc!fennimore!rwth-aachen!lvasiliev From: lvasiliev@rwth-aachen.de (Liam Vasiliev) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Dec11.181202.4047@rwth-aachen.de> Date: Sun, 11 Dec 1994 18:12:02 GMT References: <1994Dec10.035102.6754@purdue.edu> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: Netscape 1.1N Lines: 12 In article <1994Dec10.035102.6754@purdue.edu>, dnovak@purdue.edu (Dong-hyun Novak) 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. 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. -- === Liam Vasiliev === Dept of Electrical Engineering, RWTH Aachen Informatik "5 sigma is a discovery. 7 is a question." From kpopov@mindspring.com Tue Dec 13 07:02:02 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!mindspring!kpopov From: kpopov@mindspring.com (Karen Popov) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Dec13.070202.6133@mindspring.com> Date: Tue, 13 Dec 1994 07:02:02 GMT References: <1994Dec10.035102.6754@purdue.edu> <1994Dec11.181202.4047@rwth-aachen.de> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Dec11.181202.4047@rwth-aachen.de>, lvasiliev@rwth-aachen.de (Liam Vasiliev) writes: > 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. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. -- Karen Popov *PLONK* filter active for trolls. Amiga 1200 (Blizzard 030/50) - NetBSD 1.0 From seriksson@pacbell.net Tue Dec 13 14:23:02 1994 Path: ashpoly!cascade!bigsur!pacbell!seriksson From: seriksson@pacbell.net (Sun-mi Eriksson) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Dec13.142302.6535@pacbell.net> Date: Tue, 13 Dec 1994 14:23:02 GMT References: <1994Dec10.035102.6754@purdue.edu> <1994Dec11.181202.4047@rwth-aachen.de> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1994Dec11.181202.4047@rwth-aachen.de>, lvasiliev@rwth-aachen.de (Liam Vasiliev) writes: > 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. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Sun-mi Eriksson "Tape doesn't lie at 02:14. Ears do." PC-9821Ap2 (NEC) / System 7.5.1 From tjohansson@utexas.edu Wed Dec 14 14:51:02 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!utexas!tjohansson From: tjohansson@utexas.edu (Tyler Johansson) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1994Dec14.145102.8008@utexas.edu> Date: Wed, 14 Dec 1994 14:51:02 GMT References: <1994Dec10.035102.6754@purdue.edu> <1994Dec11.181202.4047@rwth-aachen.de> <1994Dec13.142302.6535@pacbell.net> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1994Dec13.142302.6535@pacbell.net>, seriksson@pacbell.net (Sun-mi Eriksson) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. > Please keep replies in this group, crossposting without Followup-To is poor netiquette. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. PGP Public key available via finger or upon request. -- Tyler Johansson -- University of Texas at Austin "They will send a copy in my place."