From fwatanabe@delphi.com Tue Sep 05 23:48:22 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!delphi!fwatanabe From: fwatanabe@delphi.com (Fiona Watanabe) Newsgroups: comp.dsp Subject: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep05.234822.9046@delphi.com> Date: Tue, 05 Sep 1995 23:48:22 GMT Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com 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. However, when downsampling from 44.1 kHz to 64 Hz, accumulator overflow in the biquad IIR filter can destabilize the loop. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Fiona Watanabe | fwatanabe@delphi.com PGP Key fingerprint: 5C7A 20B6 CA8B BED1 "Keep the channels open." From kfournier@uni-hamburg.de Thu Sep 07 00:24:22 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!uni-hamburg!kfournier From: kfournier@uni-hamburg.de (Kenji Fournier) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep07.002422.3047@uni-hamburg.de> Date: Thu, 07 Sep 1995 00:24:22 GMT References: <1995Sep05.234822.9046@delphi.com> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Sep05.234822.9046@delphi.com>, fwatanabe@delphi.com (Fiona Watanabe) 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. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Kenji Fournier Tape trading list upon request. SASE required for international mail. From jreyes@rwth-aachen.de Thu Sep 07 23:31:22 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!rwth-aachen!jreyes From: jreyes@rwth-aachen.de (Joachim Reyes) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep07.233122.5705@rwth-aachen.de> Date: Thu, 07 Sep 1995 23:31:22 GMT References: <1995Sep05.234822.9046@delphi.com> <1995Sep07.002422.3047@uni-hamburg.de> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Sep07.002422.3047@uni-hamburg.de>, kfournier@uni-hamburg.de (Kenji Fournier) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Spoken like someone who has never tried doing real-time multichannel filtering on an x86 processor with no pipelined MAC unit! -- Joachim Reyes *PLONK* filter active for trolls. Acorn RiscPC 600 - NetBSD 1.0 From kwatanabe@netcom.com Sat Sep 09 09:41:22 1995 Path: ashpoly!cascade!mxgate!coyoacan!netcom!kwatanabe From: kwatanabe@netcom.com (Karen Watanabe) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep09.094122.8506@netcom.com> Date: Sat, 09 Sep 1995 09:41:22 GMT References: <1995Sep05.234822.9046@delphi.com> <1995Sep07.002422.3047@uni-hamburg.de> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Sep07.002422.3047@uni-hamburg.de>, kfournier@uni-hamburg.de (Kenji Fournier) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Karen Watanabe -- NETCOM On-Line Communication Services "A soul is not exclusive to biology." From amoreau@titech.ac.jp Sat Sep 09 20:11:22 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!titech!amoreau From: amoreau@titech.ac.jp (Aiko Moreau) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Sep09.201122.1003@titech.ac.jp> Date: Sat, 09 Sep 1995 20:11:22 GMT References: <1995Sep05.234822.9046@delphi.com> <1995Sep07.002422.3047@uni-hamburg.de> <1995Sep09.094122.8506@netcom.com> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Sep09.094122.8506@netcom.com>, kwatanabe@netcom.com (Karen Watanabe) writes: > Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Aiko Moreau *PLONK* filter active for trolls. 486DX4/100 (FreeBSD 2.0.5) - NetBSD 1.0