From breyes@clari.net Fri Jun 23 15:00:51 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!clari!breyes From: breyes@clari.net (Bastien Reyes) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun23.150051.4077@clari.net> Date: Fri, 23 Jun 1995 15:00:51 GMT Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net 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. 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 Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. What sampling rates are people using for their vinyl rips? 44.1 kHz or 48 kHz DAT? -- === Bastien Reyes === Dept of Electrical Engineering, ClariNet Communications Corp "The carrier frequency does not drift by accident." From aoliveira@cmu.edu Sun Jun 25 06:46:51 1995 Path: ashpoly!cascade!bigsur!cmu!aoliveira From: aoliveira@cmu.edu (Anton Oliveira) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun25.064651.8998@cmu.edu> Date: Sun, 25 Jun 1995 06:46:51 GMT References: <1995Jun23.150051.4077@clari.net> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1995Jun23.150051.4077@clari.net>, breyes@clari.net (Bastien Reyes) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. PGP Public key available via finger or upon request. -- Anton Oliveira *PLONK* filter active for trolls. Decstation 5000/200 - NetBSD 1.0 From klarsson@illinois.edu Sun Jun 25 08:11:51 1995 Path: ashpoly!cascade!mxgate!coyoacan!illinois!klarsson From: klarsson@illinois.edu (Kirsty Larsson) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun25.081151.7023@illinois.edu> Date: Sun, 25 Jun 1995 08:11:51 GMT References: <1995Jun23.150051.4077@clari.net> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: Netscape 1.1N Lines: 11 In article <1995Jun23.150051.4077@clari.net>, breyes@clari.net (Bastien Reyes) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. 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. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- === Kirsty Larsson === Dept of Electrical Engineering, University of Illinois Urbana-Champaign "Measuring a record you own is listening, not piracy."