From sstewart@cam.ac.uk Wed Jan 04 07:59:03 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!cam!sstewart From: sstewart@cam.ac.uk (Sergei Stewart) Newsgroups: comp.dsp Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan04.075903.7207@cam.ac.uk> Date: Wed, 04 Jan 1995 07:59:03 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 10 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. At 14.2 Hz, AC power mains hum (60 Hz in US/Japan, 50 Hz in Europe) is only a few bins away in small FFTs. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. MATLAB script available upon request via email. -- Sergei Stewart Tape trading list upon request. SASE required for international mail. From tchoi@cmu.edu Thu Jan 05 08:22:03 1995 Path: ashpoly!cascade!mxgate!coyoacan!cmu!tchoi From: tchoi@cmu.edu (Tyler Choi) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan05.082203.8460@cmu.edu> Date: Thu, 05 Jan 1995 08:22:03 GMT References: <1995Jan04.075903.7207@cam.ac.uk> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Jan04.075903.7207@cam.ac.uk>, sstewart@cam.ac.uk (Sergei Stewart) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > At 14.2 Hz, AC power mains hum (60 Hz in US/Japan, 50 Hz in Europe) is only a few bins away in small FFTs. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- === Tyler Choi === Dept of Electrical Engineering, Carnegie Mellon University School of CS "Extraordinary claims require extraordinary spectra." From bkarlsson@cern.ch Fri Jan 06 05:54:03 1995 Path: ashpoly!cascade!mxgate!coyoacan!cern!bkarlsson From: bkarlsson@cern.ch (Brian Karlsson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan06.055403.4932@cern.ch> Date: Fri, 06 Jan 1995 05:54:03 GMT References: <1995Jan04.075903.7207@cam.ac.uk> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Jan04.075903.7207@cam.ac.uk>, sstewart@cam.ac.uk (Sergei Stewart) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > At 14.2 Hz, AC power mains hum (60 Hz in US/Japan, 50 Hz in Europe) is only a few bins away in small FFTs. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Top-posters will be placed in my ~/.killfile without notice. -- Brian Karlsson Tape trading list upon request. SASE required for international mail. From alindqvist@titech.ac.jp Sat Jan 07 15:28:03 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!titech!alindqvist From: alindqvist@titech.ac.jp (Astrid Lindqvist) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan07.152803.6929@titech.ac.jp> Date: Sat, 07 Jan 1995 15:28:03 GMT References: <1995Jan04.075903.7207@cam.ac.uk> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Jan04.075903.7207@cam.ac.uk>, sstewart@cam.ac.uk (Sergei Stewart) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > At 14.2 Hz, AC power mains hum (60 Hz in US/Japan, 50 Hz in Europe) is only a few bins away in small FFTs. Don't forget that if you downsample to 64 Hz first, your FFT resolution jumps to 0.015 Hz per bin with a modest 4096-point transform. -- Astrid Lindqvist *PLONK* filter active for trolls. Atari Falcon 030 - NetBSD 1.0