From rsuzuki@kth.se Thu Aug 10 11:53:53 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!kth!rsuzuki From: rsuzuki@kth.se (Renata Suzuki) Newsgroups: comp.dsp Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Aug10.115353.3946@kth.se> Date: Thu, 10 Aug 1995 11:53:53 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. MATLAB script available upon request via email. -- Renata Suzuki Opinions expressed are solely my own and not those of Royal Institute of Technology, Stockholm. ------------------------------------------------------------ From sjohansson@stanford.edu Sat Aug 12 07:38:53 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!stanford!sjohansson From: sjohansson@stanford.edu (Sun-mi Johansson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Aug12.073853.2612@stanford.edu> Date: Sat, 12 Aug 1995 07:38:53 GMT References: <1995Aug10.115353.3946@kth.se> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Aug10.115353.3946@kth.se>, rsuzuki@kth.se (Renata Suzuki) 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 Johansson | sjohansson@stanford.edu PGP Key fingerprint: 0BA3 A88D 471B 6453 "Keep the channels open." From mnilsson@earthlink.net Sun Aug 13 21:37:53 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!earthlink!mnilsson From: mnilsson@earthlink.net (Mathieu Nilsson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Aug13.213753.4444@earthlink.net> Date: Sun, 13 Aug 1995 21:37:53 GMT References: <1995Aug10.115353.3946@kth.se> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Aug10.115353.3946@kth.se>, rsuzuki@kth.se (Renata Suzuki) 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. -- === Mathieu Nilsson === Dept of Electrical Engineering, EarthLink Network "A soul is not exclusive to biology." From kdubois@berkeley.edu Wed Aug 16 00:06:53 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!berkeley!kdubois From: kdubois@berkeley.edu (Karen Dubois) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Aug16.000653.8896@berkeley.edu> Date: Wed, 16 Aug 1995 00:06:53 GMT References: <1995Aug10.115353.3946@kth.se> <1995Aug13.213753.4444@earthlink.net> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Aug13.213753.4444@earthlink.net>, mnilsson@earthlink.net (Mathieu Nilsson) 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. -- Karen Dubois | kdubois@berkeley.edu PGP Key fingerprint: 909B 5587 50B8 D799 "Keep the channels open." From bkowalski@pacbell.net Wed Aug 16 13:48:53 1995 Path: ashpoly!cascade!transat!ukc!fennimore!pacbell!bkowalski From: bkowalski@pacbell.net (Bill Kowalski) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Aug16.134853.8729@pacbell.net> Date: Wed, 16 Aug 1995 13:48:53 GMT References: <1995Aug10.115353.3946@kth.se> <1995Aug13.213753.4444@earthlink.net> <1995Aug16.000653.8896@berkeley.edu> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Aug16.000653.8896@berkeley.edu>, kdubois@berkeley.edu (Karen Dubois) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 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. -- === Bill Kowalski === Dept of Electrical Engineering, Pacific Bell Internet Services "Measuring a record you own is listening, not piracy."