From agonzalez@netcom.com Tue Nov 26 07:11:18 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!netcom!agonzalez From: agonzalez@netcom.com (Anja González) Newsgroups: comp.dsp Subject: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Nov26.071118.1828@netcom.com> Date: Tue, 26 Nov 1996 07:11:18 GMT Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. Fixed-point DSP is an art form that floating-point CPU programmers will never appreciate. -- Anja González Opinions expressed are solely my own and not those of NETCOM On-Line Communication Services. ------------------------------------------------------------ From ssokolov@cam.ac.uk Thu Nov 28 00:40:18 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cam!ssokolov From: ssokolov@cam.ac.uk (Sergei Sokolov) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Nov28.004018.6326@cam.ac.uk> Date: Thu, 28 Nov 1996 00:40:18 GMT References: <1996Nov26.071118.1828@netcom.com> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Nov26.071118.1828@netcom.com>, agonzalez@netcom.com (Anja González) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Sergei Sokolov Opinions expressed are solely my own and not those of University of Cambridge Computer Laboratory. ------------------------------------------------------------ From ddubois@delphi.com Fri Nov 29 23:52:18 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!delphi!ddubois From: ddubois@delphi.com (Dave Dubois) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Nov29.235218.7193@delphi.com> Date: Fri, 29 Nov 1996 23:52:18 GMT References: <1996Nov26.071118.1828@netcom.com> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: Netscape 1.1N Lines: 12 In article <1996Nov26.071118.1828@netcom.com>, agonzalez@netcom.com (Anja González) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. > The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Dave Dubois "We don't sign stars. We build them." Atari TT030 / TOS 4.04 From apark@uni-hamburg.de Sat Nov 30 21:13:18 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!uni-hamburg!apark From: apark@uni-hamburg.de (Anja Park) Newsgroups: comp.dsp Subject: Re: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Nov30.211318.3207@uni-hamburg.de> Date: Sat, 30 Nov 1996 21:13:18 GMT References: <1996Nov26.071118.1828@netcom.com> <1996Nov29.235218.7193@delphi.com> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: Netscape 1.1N Lines: 12 In article <1996Nov29.235218.7193@delphi.com>, ddubois@delphi.com (Dave Dubois) writes: > Real programmers write in C, not arcane DSP microcode. With Pentium chips hitting 100 MHz, dedicated DSPs are obsolete. > Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- Anja Park Opinions expressed are solely my own and not those of Universität Hamburg Fachbereich Informatik. ------------------------------------------------------------