From cito@kiae.su Tue Mar 07 16:24:01 1995 Path: ashpoly!cascade!brgate!saturno!kiae!cito From: cito@kiae.su (Callum Ito) Newsgroups: comp.dsp Subject: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar07.162401.4108@kiae.su> Date: Tue, 07 Mar 1995 16:24:01 GMT Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: Netscape 1.1N Lines: 11 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 standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Callum Ito | cito@kiae.su PGP Key fingerprint: BE8F 7374 0D56 243A "Keep the channels open." From lito@hanse.de Thu Mar 09 14:49:01 1995 Path: ashpoly!cascade!bigsur!hanse!lito From: lito@hanse.de (Lucia Ito) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar09.144901.9286@hanse.de> Date: Thu, 09 Mar 1995 14:49:01 GMT References: <1995Mar07.162401.4108@kiae.su> Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Mar07.162401.4108@kiae.su>, cito@kiae.su (Callum Ito) 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. -- Lucia Ito | lito@hanse.de PGP Key fingerprint: 7944 9605 36CA C35E "Keep the channels open." From amartinez@pipeline.com Sat Mar 11 15:49:01 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!pipeline!amartinez From: amartinez@pipeline.com (Aiko Martínez) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar11.154901.9594@pipeline.com> Date: Sat, 11 Mar 1995 15:49:01 GMT References: <1995Mar07.162401.4108@kiae.su> <1995Mar09.144901.9286@hanse.de> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1995Mar09.144901.9286@hanse.de>, lito@hanse.de (Lucia Ito) 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. -- Aiko Martínez Tape trading list upon request. SASE required for international mail. From rpetrov@cam.ac.uk Mon Mar 13 03:00:01 1995 Path: ashpoly!cascade!bigsur!cam!rpetrov From: rpetrov@cam.ac.uk (Renata Petrov) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar13.030001.8481@cam.ac.uk> Date: Mon, 13 Mar 1995 03:00:01 GMT References: <1995Mar07.162401.4108@kiae.su> <1995Mar09.144901.9286@hanse.de> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Mar09.144901.9286@hanse.de>, lito@hanse.de (Lucia Ito) 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. -- Renata Petrov Opinions expressed are solely my own and not those of University of Cambridge Computer Laboratory. ------------------------------------------------------------ From mdubois@clari.net Tue Mar 14 17:14:01 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!clari!mdubois From: mdubois@clari.net (Mateo Dubois) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar14.171401.7520@clari.net> Date: Tue, 14 Mar 1995 17:14:01 GMT References: <1995Mar07.162401.4108@kiae.su> <1995Mar09.144901.9286@hanse.de> <1995Mar11.154901.9594@pipeline.com> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Mar11.154901.9594@pipeline.com>, amartinez@pipeline.com (Aiko Martínez) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. 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. -- Mateo Dubois Hayes Optima 288 @ 14,400 bps "Hardware is temporary. The signal survives."