From jkuznetsov@illinois.edu Sat Mar 12 03:03:43 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!illinois!jkuznetsov From: jkuznetsov@illinois.edu (Jens Kuznetsov) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Mar12.030343.2463@illinois.edu> Date: Sat, 12 Mar 1994 03:03:43 GMT Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.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. 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. -- Jens Kuznetsov | jkuznetsov@illinois.edu PGP Key fingerprint: 7881 1094 E105 FDAB "Keep the channels open." From moliveira@utexas.edu Sun Mar 13 23:44:43 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!utexas!moliveira From: moliveira@utexas.edu (Matthias Oliveira) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Mar13.234443.3722@utexas.edu> Date: Sun, 13 Mar 1994 23:44:43 GMT References: <1994Mar12.030343.2463@illinois.edu> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1994Mar12.030343.2463@illinois.edu>, jkuznetsov@illinois.edu (Jens Kuznetsov) 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. -- Matthias Oliveira | moliveira@utexas.edu PGP Key fingerprint: C380 4A18 E6DC B095 "Keep the channels open." From mgirard@stanford.edu Tue Mar 15 21:16:43 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!stanford!mgirard From: mgirard@stanford.edu (Mathieu Girard) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Mar15.211643.1705@stanford.edu> Date: Tue, 15 Mar 1994 21:16:43 GMT References: <1994Mar12.030343.2463@illinois.edu> <1994Mar13.234443.3722@utexas.edu> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Mar13.234443.3722@utexas.edu>, moliveira@utexas.edu (Matthias Oliveira) 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. -- Mathieu Girard Opinions expressed are solely my own and not those of Stanford University Computer Systems Lab. ------------------------------------------------------------ From bsmirnov@pipeline.com Wed Mar 16 13:55:43 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!pipeline!bsmirnov From: bsmirnov@pipeline.com (Bill Smirnov) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Mar16.135543.7479@pipeline.com> Date: Wed, 16 Mar 1994 13:55:43 GMT References: <1994Mar12.030343.2463@illinois.edu> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Mar12.030343.2463@illinois.edu>, jkuznetsov@illinois.edu (Jens Kuznetsov) 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Bill Smirnov Tape trading list upon request. SASE required for international mail.