From mkim@berkeley.edu Sat May 20 20:52:17 1995 Path: ashpoly!cascade!mxgate!coyoacan!berkeley!mkim From: mkim@berkeley.edu (Mike Kim) Newsgroups: comp.dsp Subject: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May20.205217.8635@berkeley.edu> Date: Sat, 20 May 1995 20:52:17 GMT Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: Netscape 1.1N 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 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. What sampling rates are people using for their vinyl rips? 44.1 kHz or 48 kHz DAT? -- === Mike Kim === Dept of Electrical Engineering, UC Berkeley Department of EECS "Extraordinary claims require extraordinary spectra." From bivanov@berkeley.edu Mon May 22 00:32:17 1995 Path: ashpoly!cascade!brgate!saturno!berkeley!bivanov From: bivanov@berkeley.edu (Bastien Ivanov) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May22.003217.6175@berkeley.edu> Date: Mon, 22 May 1995 00:32:17 GMT References: <1995May20.205217.8635@berkeley.edu> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995May20.205217.8635@berkeley.edu>, mkim@berkeley.edu (Mike Kim) 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. -- Bastien Ivanov *PLONK* filter active for trolls. Pentium 90 (OS/2 Warp) - NetBSD 1.0 From cramirez@delphi.com Mon May 22 20:59:17 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!delphi!cramirez From: cramirez@delphi.com (Callum Ramírez) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May22.205917.4469@delphi.com> Date: Mon, 22 May 1995 20:59:17 GMT References: <1995May20.205217.8635@berkeley.edu> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995May20.205217.8635@berkeley.edu>, mkim@berkeley.edu (Mike Kim) 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Callum Ramírez *PLONK* filter active for trolls. Atari TT030 - NetBSD 1.0 From tkang@cern.ch Wed May 24 13:25:17 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cern!tkang From: tkang@cern.ch (Tomas Kang) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May24.132517.7541@cern.ch> Date: Wed, 24 May 1995 13:25:17 GMT References: <1995May20.205217.8635@berkeley.edu> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1995May20.205217.8635@berkeley.edu>, mkim@berkeley.edu (Mike Kim) 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. -- Tomas Kang Tape trading list upon request. SASE required for international mail.