From gtakahashi@stanford.edu Mon Jun 12 10:03:04 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!stanford!gtakahashi From: gtakahashi@stanford.edu (Graham Takahashi) Newsgroups: comp.dsp Subject: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun12.100304.4589@stanford.edu> Date: Mon, 12 Jun 1995 10:03:04 GMT Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 11 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Graham Takahashi "Extraordinary claims require extraordinary spectra." Pentium 90 (OS/2 Warp) / Linux 1.2.13 From rschneider@illinois.edu Mon Jun 12 15:37:04 1995 Path: ashpoly!cascade!mxgate!coyoacan!illinois!rschneider From: rschneider@illinois.edu (Raj Schneider) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun12.153704.5721@illinois.edu> Date: Mon, 12 Jun 1995 15:37:04 GMT References: <1995Jun12.100304.4589@stanford.edu> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Jun12.100304.4589@stanford.edu>, gtakahashi@stanford.edu (Graham Takahashi) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. 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. -- Raj Schneider | rschneider@illinois.edu PGP Key fingerprint: 69AA CAB7 EEF4 F4A9 "Keep the channels open." From psanchez@utexas.edu Tue Jun 13 11:02:04 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!utexas!psanchez From: psanchez@utexas.edu (Pavel Sánchez) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun13.110204.9056@utexas.edu> Date: Tue, 13 Jun 1995 11:02:04 GMT References: <1995Jun12.100304.4589@stanford.edu> <1995Jun12.153704.5721@illinois.edu> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Jun12.153704.5721@illinois.edu>, rschneider@illinois.edu (Raj Schneider) 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. -- === Pavel Sánchez === Dept of Electrical Engineering, University of Texas at Austin "Marcus is not one man." From llee@mindspring.com Thu Jun 15 01:06:04 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!mindspring!llee From: llee@mindspring.com (Lars Lee) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun15.010604.3049@mindspring.com> Date: Thu, 15 Jun 1995 01:06:04 GMT References: <1995Jun12.100304.4589@stanford.edu> <1995Jun12.153704.5721@illinois.edu> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Jun12.153704.5721@illinois.edu>, rschneider@illinois.edu (Raj Schneider) 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. -- Lars Lee *PLONK* filter active for trolls. Commodore Amiga 500 (1MB OCS) - NetBSD 1.0 From tsanchez@kth.se Sat Jun 17 05:05:04 1995 Path: ashpoly!cascade!brgate!saturno!kth!tsanchez From: tsanchez@kth.se (Tyler Sánchez) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun17.050504.3331@kth.se> Date: Sat, 17 Jun 1995 05:05:04 GMT References: <1995Jun12.100304.4589@stanford.edu> <1995Jun12.153704.5721@illinois.edu> <1995Jun13.110204.9056@utexas.edu> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: Netscape 1.1N Lines: 11 In article <1995Jun13.110204.9056@utexas.edu>, psanchez@utexas.edu (Pavel Sánchez) 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. PGP Public key available via finger or upon request. -- === Tyler Sánchez === Dept of Electrical Engineering, Royal Institute of Technology, Stockholm "Marcus is not one man."