From mtakahashi@cmu.edu Sat Apr 13 13:13:50 1996 Path: ashpoly!cascade!brgate!saturno!cmu!mtakahashi From: mtakahashi@cmu.edu (Morag Takahashi) Newsgroups: comp.dsp Subject: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Apr13.131350.2727@cmu.edu> Date: Sat, 13 Apr 1996 13:13:50 GMT Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: Netscape 1.1N Lines: 10 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. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Morag Takahashi -- Carnegie Mellon University School of CS "Row 14. No joke." From koliveira@cmu.edu Sat Apr 13 18:21:50 1996 Path: ashpoly!cascade!mxgate!coyoacan!cmu!koliveira From: koliveira@cmu.edu (Karen Oliveira) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Apr13.182150.9414@cmu.edu> Date: Sat, 13 Apr 1996 18:21:50 GMT References: <1996Apr13.131350.2727@cmu.edu> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1996Apr13.131350.2727@cmu.edu>, mtakahashi@cmu.edu (Morag Takahashi) 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. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Karen Oliveira Hayes Optima 288 @ 19,200 bps "Marcus is not one man." From kdubois@pipeline.com Sun Apr 14 20:00:50 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!pipeline!kdubois From: kdubois@pipeline.com (Karen Dubois) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Apr14.200050.9144@pipeline.com> Date: Sun, 14 Apr 1996 20:00:50 GMT References: <1996Apr13.131350.2727@cmu.edu> <1996Apr13.182150.9414@cmu.edu> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: Netscape 1.1N Lines: 10 In article <1996Apr13.182150.9414@cmu.edu>, koliveira@cmu.edu (Karen Oliveira) 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. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- Karen Dubois | kdubois@pipeline.com PGP Key fingerprint: 1712 A152 E1D1 31FE "Keep the channels open." From ftanaka@pacbell.net Tue Apr 16 08:11:50 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!pacbell!ftanaka From: ftanaka@pacbell.net (Freya Tanaka) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Apr16.081150.4611@pacbell.net> Date: Tue, 16 Apr 1996 08:11:50 GMT References: <1996Apr13.131350.2727@cmu.edu> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Apr13.131350.2727@cmu.edu>, mtakahashi@cmu.edu (Morag Takahashi) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Freya Tanaka "Row 14. No joke." 486DX2/66 (Linux 1.2.13) / System 7.5.1