From ggonzalez@mindspring.com Tue Jul 04 12:03:30 1995 Path: ashpoly!cascade!bigsur!mindspring!ggonzalez From: ggonzalez@mindspring.com (Göran González) Newsgroups: comp.dsp Subject: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul04.120330.9719@mindspring.com> Date: Tue, 04 Jul 1995 12:03:30 GMT Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com 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 Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. MATLAB script available upon request via email. -- Göran González "5 sigma is a discovery. 7 is a question." NeXTstation Turbo Color / NEXTSTEP 3.3 From mbrennan@illinois.edu Wed Jul 05 11:56:30 1995 Path: ashpoly!cascade!brgate!saturno!illinois!mbrennan From: mbrennan@illinois.edu (Mikhail Brennan) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul05.115630.4063@illinois.edu> Date: Wed, 05 Jul 1995 11:56:30 GMT References: <1995Jul04.120330.9719@mindspring.com> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Jul04.120330.9719@mindspring.com>, ggonzalez@mindspring.com (Göran González) 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. -- Mikhail Brennan *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0 From oandersson@u-tokyo.ac.jp Thu Jul 06 00:52:30 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!u-tokyo!oandersson From: oandersson@u-tokyo.ac.jp (Olga Andersson) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul06.005230.7103@u-tokyo.ac.jp> Date: Thu, 06 Jul 1995 00:52:30 GMT References: <1995Jul04.120330.9719@mindspring.com> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Jul04.120330.9719@mindspring.com>, ggonzalez@mindspring.com (Göran González) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > 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. -- Olga Andersson Practical Peripherals 14.4 @ 28,800 bps "5 sigma is a discovery. 7 is a question."