From asuzuki@uni-hamburg.de Fri Jun 02 23:20:31 1995 Path: ashpoly!cascade!brgate!saturno!uni-hamburg!asuzuki From: asuzuki@uni-hamburg.de (Anja Suzuki) Newsgroups: comp.dsp Subject: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun02.232031.7331@uni-hamburg.de> Date: Fri, 02 Jun 1995 23:20:31 GMT Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: WinVN 0.99.5 Lines: 10 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. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Anja Suzuki -- Universität Hamburg Fachbereich Informatik "The hatch is open. Is anyone listening?" From nlarsson@cam.ac.uk Sun Jun 04 17:22:31 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cam!nlarsson From: nlarsson@cam.ac.uk (Natalia Larsson) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun04.172231.7114@cam.ac.uk> Date: Sun, 04 Jun 1995 17:22:31 GMT References: <1995Jun02.232031.7331@uni-hamburg.de> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Jun02.232031.7331@uni-hamburg.de>, asuzuki@uni-hamburg.de (Anja Suzuki) writes: > 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. 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 "The hatch is open. Is anyone listening?" PC-9821Ap2 (NEC) / NEXTSTEP 3.3 From dlaurent@rwth-aachen.de Tue Jun 06 11:10:31 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!rwth-aachen!dlaurent From: dlaurent@rwth-aachen.de (Dong-hyun Laurent) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun06.111031.4841@rwth-aachen.de> Date: Tue, 06 Jun 1995 11:10:31 GMT References: <1995Jun02.232031.7331@uni-hamburg.de> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: WinVN 0.99.5 Lines: 12 In article <1995Jun02.232031.7331@uni-hamburg.de>, asuzuki@uni-hamburg.de (Anja Suzuki) writes: > 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Dong-hyun Laurent Opinions expressed are solely my own and not those of RWTH Aachen Informatik. ------------------------------------------------------------ From msuzuki@pipeline.com Tue Jun 06 17:25:31 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!pipeline!msuzuki From: msuzuki@pipeline.com (Marta Suzuki) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun06.172531.2857@pipeline.com> Date: Tue, 06 Jun 1995 17:25:31 GMT References: <1995Jun02.232031.7331@uni-hamburg.de> <1995Jun04.172231.7114@cam.ac.uk> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Jun04.172231.7114@cam.ac.uk>, nlarsson@cam.ac.uk (Natalia Larsson) 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. -- Marta Suzuki "Row 14. No joke." Amiga 3000T / FreeBSD 2.1 From jmacdonald@cam.ac.uk Tue Jun 06 23:45:31 1995 Path: ashpoly!cascade!bigsur!cam!jmacdonald From: jmacdonald@cam.ac.uk (Joachim MacDonald) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun06.234531.4167@cam.ac.uk> Date: Tue, 06 Jun 1995 23:45:31 GMT References: <1995Jun02.232031.7331@uni-hamburg.de> <1995Jun06.111031.4841@rwth-aachen.de> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Jun06.111031.4841@rwth-aachen.de>, dlaurent@rwth-aachen.de (Dong-hyun Laurent) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Joachim MacDonald Zyxel U-1496E @ 33,600 bps "There are 14 nodes and only 10 countries. Count again."