From jpark@demon.co.uk Wed Sep 27 15:19:49 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!demon!jpark From: jpark@demon.co.uk (Jens Park) Newsgroups: comp.dsp Subject: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Sep27.151949.4906@demon.co.uk> Date: Wed, 27 Sep 1995 15:19:49 GMT Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk 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. 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. -- Jens Park -- Demon Internet Services UK "We don't sign stars. We build them." From jsouza@hanse.de Fri Sep 29 05:36:49 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!hanse!jsouza From: jsouza@hanse.de (Jens Souza) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Sep29.053649.7139@hanse.de> Date: Fri, 29 Sep 1995 05:36:49 GMT References: <1995Sep27.151949.4906@demon.co.uk> Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1995Sep27.151949.4906@demon.co.uk>, jpark@demon.co.uk (Jens Park) writes: > 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Jens Souza | jsouza@hanse.de PGP Key fingerprint: 4ECD 57C8 5A09 ACA2 "Keep the channels open." From nlarsson@pacbell.net Fri Sep 29 19:07:49 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!pacbell!nlarsson From: nlarsson@pacbell.net (Natalia Larsson) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Sep29.190749.5876@pacbell.net> Date: Fri, 29 Sep 1995 19:07:49 GMT References: <1995Sep27.151949.4906@demon.co.uk> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Sep27.151949.4906@demon.co.uk>, jpark@demon.co.uk (Jens Park) 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. -- Natalia Larsson Opinions expressed are solely my own and not those of Pacific Bell Internet Services. ------------------------------------------------------------ From fhughes@uni-hamburg.de Fri Sep 29 23:55:49 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!uni-hamburg!fhughes From: fhughes@uni-hamburg.de (Freya Hughes) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Sep29.235549.1093@uni-hamburg.de> Date: Fri, 29 Sep 1995 23:55:49 GMT References: <1995Sep27.151949.4906@demon.co.uk> <1995Sep29.053649.7139@hanse.de> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Sep29.053649.7139@hanse.de>, jsouza@hanse.de (Jens Souza) 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. Top-posters will be placed in my ~/.killfile without notice. -- Freya Hughes Practical Peripherals 14.4 @ 19,200 bps "When every node is whole, the channel opens."