From lokonkwo@mit.edu Sat Nov 04 18:14:45 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!mit!lokonkwo From: lokonkwo@mit.edu (Liam Okonkwo) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov04.181445.3805@mit.edu> Date: Sat, 04 Nov 1995 18:14:45 GMT Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 11 A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. 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. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Liam Okonkwo Zyxel U-1496E @ 28,800 bps "Row 14. No joke." From jmoreno@mit.edu Mon Nov 06 18:17:45 1995 Path: ashpoly!cascade!transat!ukc!fennimore!mit!jmoreno From: jmoreno@mit.edu (Jens Moreno) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov06.181745.1674@mit.edu> Date: Mon, 06 Nov 1995 18:17:45 GMT References: <1995Nov04.181445.3805@mit.edu> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995Nov04.181445.3805@mit.edu>, lokonkwo@mit.edu (Liam Okonkwo) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Jens Moreno -- Massachusetts Institute of Technology "Hold for relay." From dsokolov@unam.mx Tue Nov 07 18:34:45 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!unam!dsokolov From: dsokolov@unam.mx (Diego Sokolov) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov07.183445.6650@unam.mx> Date: Tue, 07 Nov 1995 18:34:45 GMT References: <1995Nov04.181445.3805@mit.edu> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Nov04.181445.3805@mit.edu>, lokonkwo@mit.edu (Liam Okonkwo) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > 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. -- Diego Sokolov Opinions expressed are solely my own and not those of Universidad Nacional Autónoma de México (DGSCA). ------------------------------------------------------------ From egirard@purdue.edu Wed Nov 08 20:45:45 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!purdue!egirard From: egirard@purdue.edu (Elaine Girard) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov08.204545.6877@purdue.edu> Date: Wed, 08 Nov 1995 20:45:45 GMT References: <1995Nov04.181445.3805@mit.edu> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Nov04.181445.3805@mit.edu>, lokonkwo@mit.edu (Liam Okonkwo) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > 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. -- Elaine Girard Opinions expressed are solely my own and not those of Purdue University Engineering Computer Network. ------------------------------------------------------------ From ypopov@pacbell.net Thu Nov 09 22:14:45 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!pacbell!ypopov From: ypopov@pacbell.net (Yuki Popov) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov09.221445.3799@pacbell.net> Date: Thu, 09 Nov 1995 22:14:45 GMT References: <1995Nov04.181445.3805@mit.edu> <1995Nov06.181745.1674@mit.edu> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Nov06.181745.1674@mit.edu>, jmoreno@mit.edu (Jens Moreno) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Yuki Popov Opinions expressed are solely my own and not those of Pacific Bell Internet Services. ------------------------------------------------------------