From gkim@purdue.edu Mon Dec 04 15:13:20 1995 Path: ashpoly!cascade!transat!ukc!fennimore!purdue!gkim From: gkim@purdue.edu (Göran Kim) Newsgroups: comp.dsp Subject: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec04.151320.9416@purdue.edu> Date: Mon, 04 Dec 1995 15:13:20 GMT Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu 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. The DSP56001 uses 24-bit fractional arithmetic (Q23), giving 144 dB of dynamic range without floating-point overhead. Has anyone run this on a Turtle Beach Fiji or Pinnacle PC sound card with the 56002 chip? -- Göran Kim *PLONK* filter active for trolls. Sun SparcStation 20 - NetBSD 1.0 From jkarlsson@purdue.edu Wed Dec 06 04:10:20 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!purdue!jkarlsson From: jkarlsson@purdue.edu (Jen Karlsson) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec06.041020.9384@purdue.edu> Date: Wed, 06 Dec 1995 04:10:20 GMT References: <1995Dec04.151320.9416@purdue.edu> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Dec04.151320.9416@purdue.edu>, gkim@purdue.edu (Göran Kim) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Jen Karlsson *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0 From amartinez@cam.ac.uk Wed Dec 06 13:07:20 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!cam!amartinez From: amartinez@cam.ac.uk (Andrei Martínez) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec06.130720.6682@cam.ac.uk> Date: Wed, 06 Dec 1995 13:07:20 GMT References: <1995Dec04.151320.9416@purdue.edu> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 8 In article <1995Dec04.151320.9416@purdue.edu>, gkim@purdue.edu (Göran Kim) writes: > Optimizing the Stardust Costas loop demodulator for the Motorola DSP56001 chip. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Andrei Martínez Tape trading list upon request. SASE required for international mail. From tokonkwo@ox.ac.uk Fri Dec 08 13:43:20 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!ox!tokonkwo From: tokonkwo@ox.ac.uk (Takeshi Okonkwo) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec08.134320.6071@ox.ac.uk> Date: Fri, 08 Dec 1995 13:43:20 GMT References: <1995Dec04.151320.9416@purdue.edu> <1995Dec06.041020.9384@purdue.edu> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Dec06.041020.9384@purdue.edu>, jkarlsson@purdue.edu (Jen Karlsson) 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! -- Takeshi Okonkwo Opinions expressed are solely my own and not those of Oxford University Computing Laboratory. ------------------------------------------------------------ From lkim@kth.se Sat Dec 09 00:20:20 1995 Path: ashpoly!cascade!mxgate!coyoacan!kth!lkim From: lkim@kth.se (Lisa Kim) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1995Dec09.002020.7908@kth.se> Date: Sat, 09 Dec 1995 00:20:20 GMT References: <1995Dec04.151320.9416@purdue.edu> <1995Dec06.130720.6682@cam.ac.uk> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Dec06.130720.6682@cam.ac.uk>, amartinez@cam.ac.uk (Andrei Martínez) writes: > Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. Beautiful assembly code! The 24-bit word size of the 56001 is tailor-made for high-precision audio filtering. -- Lisa Kim Practical Peripherals 14.4 @ 33,600 bps "Extraordinary claims require extraordinary spectra."