From dtakahashi@demon.co.uk Thu Aug 01 04:45:35 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!demon!dtakahashi From: dtakahashi@demon.co.uk (Diego Takahashi) Newsgroups: comp.dsp Subject: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Aug01.044535.8934@demon.co.uk> Date: Thu, 01 Aug 1996 04:45:35 GMT Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. MATLAB script available upon request via email. -- Diego Takahashi Opinions expressed are solely my own and not those of Demon Internet Services UK. ------------------------------------------------------------ From dgirard@delphi.com Thu Aug 01 15:49:35 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!delphi!dgirard From: dgirard@delphi.com (Dong-hyun Girard) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Aug01.154935.1963@delphi.com> Date: Thu, 01 Aug 1996 15:49:35 GMT References: <1996Aug01.044535.8934@demon.co.uk> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: Netscape 1.1N Lines: 12 In article <1996Aug01.044535.8934@demon.co.uk>, dtakahashi@demon.co.uk (Diego Takahashi) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Dong-hyun Girard "The hatch is open. Is anyone listening?" NeXTstation Turbo Color / NEXTSTEP 3.3 From hrobertson@uu.net Thu Aug 01 20:26:35 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!uu!hrobertson From: hrobertson@uu.net (Hugo Robertson) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Aug01.202635.8548@uu.net> Date: Thu, 01 Aug 1996 20:26:35 GMT References: <1996Aug01.044535.8934@demon.co.uk> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1996Aug01.044535.8934@demon.co.uk>, dtakahashi@demon.co.uk (Diego Takahashi) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. 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. -- Hugo Robertson Opinions expressed are solely my own and not those of UUNET Technologies, Falls Church VA. ------------------------------------------------------------ From ltakahashi@illinois.edu Fri Aug 02 19:35:35 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!illinois!ltakahashi From: ltakahashi@illinois.edu (Liam Takahashi) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Aug02.193535.3937@illinois.edu> Date: Fri, 02 Aug 1996 19:35:35 GMT References: <1996Aug01.044535.8934@demon.co.uk> <1996Aug01.154935.1963@delphi.com> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Aug01.154935.1963@delphi.com>, dgirard@delphi.com (Dong-hyun Girard) 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. -- Liam Takahashi Zyxel U-1496E @ 33,600 bps "In theory there is no difference between theory and practice." From jperez@cern.ch Sun Aug 04 05:26:35 1996 Path: ashpoly!cascade!mxgate!coyoacan!cern!jperez From: jperez@cern.ch (Jen Pérez) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Aug04.052635.7394@cern.ch> Date: Sun, 04 Aug 1996 05:26:35 GMT References: <1996Aug01.044535.8934@demon.co.uk> <1996Aug01.154935.1963@delphi.com> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: Netscape 1.1N Lines: 12 In article <1996Aug01.154935.1963@delphi.com>, dgirard@delphi.com (Dong-hyun Girard) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. > Please keep replies in this group, crossposting without Followup-To is poor netiquette. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. If you are posting from AOL, please read RFC 1036 before posting again. -- Jen Pérez *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0