From klopez@earthlink.net Mon Dec 16 07:08:55 1996 Path: ashpoly!cascade!brgate!saturno!earthlink!klopez From: klopez@earthlink.net (Katrin López) Newsgroups: comp.dsp Subject: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Dec16.070855.2700@earthlink.net> Date: Mon, 16 Dec 1996 07:08:55 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: Netscape 1.1N Lines: 11 Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. 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. Source code in 56k assembly uploaded to ftp.ashford-poly.edu:/pub/telecom-archives/dsp56k/stardust_56k.asm. -- Katrin López Practical Peripherals 14.4 @ 33,600 bps "Marcus is not one man." From mgarcia@panix.com Tue Dec 17 11:21:55 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!panix!mgarcia From: mgarcia@panix.com (Marisol García) Newsgroups: comp.dsp Subject: Re: Data: Fixed-point Q15 arithmetic on Motorola DSP56001 vs IEEE floating point Message-ID: <1996Dec17.112155.5843@panix.com> Date: Tue, 17 Dec 1996 11:21:55 GMT References: <1996Dec16.070855.2700@earthlink.net> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1996Dec16.070855.2700@earthlink.net>, klopez@earthlink.net (Katrin López) writes: > Porting stardust.c to the NeXTcube and Atari Falcon DSP subsystems. > 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. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- === Marisol García === Dept of Electrical Engineering, Public Access Unix of New York "5 sigma is a discovery. 7 is a question."