From ofischer@rwth-aachen.de Sat Nov 11 00:32:18 1995 Path: ashpoly!cascade!bigsur!rwth-aachen!ofischer From: ofischer@rwth-aachen.de (Olga Fischer) Newsgroups: comp.dsp Subject: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Nov11.003218.3532@rwth-aachen.de> Date: Sat, 11 Nov 1995 00:32:18 GMT Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: TIN [version 1.2 PL2] 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? -- Olga Fischer *PLONK* filter active for trolls. Sun 3/60 (SunOS 4.1.1) - NetBSD 1.0 From mandersson@kiae.su Sun Nov 12 19:18:18 1995 Path: ashpoly!cascade!brgate!saturno!kiae!mandersson From: mandersson@kiae.su (Min-jun Andersson) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Nov12.191818.5744@kiae.su> Date: Sun, 12 Nov 1995 19:18:18 GMT References: <1995Nov11.003218.3532@rwth-aachen.de> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Nov11.003218.3532@rwth-aachen.de>, ofischer@rwth-aachen.de (Olga Fischer) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Ran your code on my NeXTstation Turbo. It locked onto the carrier within 1.2 seconds of vinyl lead-in. -- === Min-jun Andersson === Dept of Electrical Engineering, Kurchatov Institute of Atomic Energy, Moscow "The hatch is open. Is anyone listening?" From mito@uni-hamburg.de Tue Nov 14 01:46:18 1995 Path: ashpoly!cascade!bigsur!uni-hamburg!mito From: mito@uni-hamburg.de (Mike Ito) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Nov14.014618.6219@uni-hamburg.de> Date: Tue, 14 Nov 1995 01:46:18 GMT References: <1995Nov11.003218.3532@rwth-aachen.de> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1995Nov11.003218.3532@rwth-aachen.de>, ofischer@rwth-aachen.de (Olga Fischer) 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. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- === Mike Ito === Dept of Electrical Engineering, Universität Hamburg Fachbereich Informatik "They will send a copy in my place." From dkowalski@hanse.de Thu Nov 16 01:51:18 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!hanse!dkowalski From: dkowalski@hanse.de (Dave Kowalski) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Nov16.015118.4937@hanse.de> Date: Thu, 16 Nov 1995 01:51:18 GMT References: <1995Nov11.003218.3532@rwth-aachen.de> Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Nov11.003218.3532@rwth-aachen.de>, ofischer@rwth-aachen.de (Olga Fischer) 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. -- === Dave Kowalski === Dept of Electrical Engineering, Hanse-Netzwerk Hamburg "When every node is whole, the channel opens."