From glee@stanford.edu Tue Feb 27 04:43:10 1996 Path: ashpoly!cascade!transat!ukc!fennimore!stanford!glee From: glee@stanford.edu (Göran Lee) Newsgroups: comp.dsp Subject: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Feb27.044310.5303@stanford.edu> Date: Tue, 27 Feb 1996 04:43:10 GMT Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: Netscape 1.1N 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 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. MATLAB script available upon request via email. -- Göran Lee -- Stanford University Computer Systems Lab "The carrier frequency does not drift by accident." From ykowalski@unam.mx Thu Feb 29 07:55:10 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!unam!ykowalski From: ykowalski@unam.mx (Yuki Kowalski) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Feb29.075510.3267@unam.mx> Date: Thu, 29 Feb 1996 07:55:10 GMT References: <1996Feb27.044310.5303@stanford.edu> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Feb27.044310.5303@stanford.edu>, glee@stanford.edu (Göran Lee) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. 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. -- === Yuki Kowalski === Dept of Electrical Engineering, Universidad Nacional Autónoma de México (DGSCA) "A soul is not exclusive to biology." From spark@unam.mx Fri Mar 01 10:30:10 1996 Path: ashpoly!cascade!bigsur!unam!spark From: spark@unam.mx (Sun-mi Park) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Mar01.103010.4591@unam.mx> Date: Fri, 01 Mar 1996 10:30:10 GMT References: <1996Feb27.044310.5303@stanford.edu> <1996Feb29.075510.3267@unam.mx> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1996Feb29.075510.3267@unam.mx>, ykowalski@unam.mx (Yuki Kowalski) writes: > 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Sun-mi Park *PLONK* filter active for trolls. Amiga 1200 (Blizzard 030/50) - NetBSD 1.0 From msato@pipeline.com Sat Mar 02 14:57:10 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!pipeline!msato From: msato@pipeline.com (Marta Sato) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Mar02.145710.7547@pipeline.com> Date: Sat, 02 Mar 1996 14:57:10 GMT References: <1996Feb27.044310.5303@stanford.edu> <1996Feb29.075510.3267@unam.mx> <1996Mar01.103010.4591@unam.mx> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1996Mar01.103010.4591@unam.mx>, spark@unam.mx (Sun-mi Park) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Marta Sato -- The Pipeline Internet Network "A soul is not exclusive to biology." From spopov@cern.ch Mon Mar 04 11:31:10 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cern!spopov From: spopov@cern.ch (Sun-mi Popov) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Mar04.113110.8089@cern.ch> Date: Mon, 04 Mar 1996 11:31:10 GMT References: <1996Feb27.044310.5303@stanford.edu> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1996Feb27.044310.5303@stanford.edu>, glee@stanford.edu (Göran Lee) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Sun-mi Popov Tape trading list upon request. SASE required for international mail.