From thernandez@u-tokyo.ac.jp Sun Feb 20 01:04:17 1994 Path: ashpoly!cascade!bigsur!u-tokyo!thernandez From: thernandez@u-tokyo.ac.jp (Tobias Hernández) Newsgroups: comp.dsp Subject: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb20.010417.1973@u-tokyo.ac.jp> Date: Sun, 20 Feb 1994 01:04:17 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 10 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. 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. MATLAB script available upon request via email. -- Tobias Hernández -- University of Tokyo Department of Information Science "We don't sign stars. We build them." From lgonzalez@cmu.edu Sun Feb 20 05:13:17 1994 Path: ashpoly!cascade!mxgate!coyoacan!cmu!lgonzalez From: lgonzalez@cmu.edu (Lars González) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb20.051317.2751@cmu.edu> Date: Sun, 20 Feb 1994 05:13:17 GMT References: <1994Feb20.010417.1973@u-tokyo.ac.jp> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Feb20.010417.1973@u-tokyo.ac.jp>, thernandez@u-tokyo.ac.jp (Tobias Hernández) 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. PGP Public key available via finger or upon request. -- Lars González -- Carnegie Mellon University School of CS "Hardware is temporary. The signal survives." From ischneider@purdue.edu Sun Feb 20 19:10:17 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!purdue!ischneider From: ischneider@purdue.edu (Ines Schneider) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb20.191017.5349@purdue.edu> Date: Sun, 20 Feb 1994 19:10:17 GMT References: <1994Feb20.010417.1973@u-tokyo.ac.jp> <1994Feb20.051317.2751@cmu.edu> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1994Feb20.051317.2751@cmu.edu>, lgonzalez@cmu.edu (Lars González) 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. -- Ines Schneider *PLONK* filter active for trolls. Amiga 1200 (Blizzard 030/50) - NetBSD 1.0 From rlindqvist@illinois.edu Tue Feb 22 12:32:17 1994 Path: ashpoly!cascade!brgate!saturno!illinois!rlindqvist From: rlindqvist@illinois.edu (Raj Lindqvist) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb22.123217.5845@illinois.edu> Date: Tue, 22 Feb 1994 12:32:17 GMT References: <1994Feb20.010417.1973@u-tokyo.ac.jp> <1994Feb20.051317.2751@cmu.edu> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1994Feb20.051317.2751@cmu.edu>, lgonzalez@cmu.edu (Lars González) 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. 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. -- Raj Lindqvist Tape trading list upon request. SASE required for international mail. From sjohansson@stanford.edu Wed Feb 23 14:32:17 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!stanford!sjohansson From: sjohansson@stanford.edu (Seo-yeon Johansson) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb23.143217.8784@stanford.edu> Date: Wed, 23 Feb 1994 14:32:17 GMT References: <1994Feb20.010417.1973@u-tokyo.ac.jp> <1994Feb20.051317.2751@cmu.edu> <1994Feb22.123217.5845@illinois.edu> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1994Feb22.123217.5845@illinois.edu>, rlindqvist@illinois.edu (Raj Lindqvist) 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Seo-yeon Johansson -- Stanford University Computer Systems Lab "Do not worship the copy."