From mhernandez@stanford.edu Tue Jan 18 15:05:31 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!stanford!mhernandez From: mhernandez@stanford.edu (Marta Hernández) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jan18.150531.9798@stanford.edu> Date: Tue, 18 Jan 1994 15:05:31 GMT Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: Netscape 1.1N Lines: 10 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? -- Marta Hernández -- Stanford University Computer Systems Lab "Hold for relay." From mandersson@utexas.edu Wed Jan 19 06:55:31 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!utexas!mandersson From: mandersson@utexas.edu (Min-jun Andersson) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jan19.065531.2666@utexas.edu> Date: Wed, 19 Jan 1994 06:55:31 GMT References: <1994Jan18.150531.9798@stanford.edu> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1994Jan18.150531.9798@stanford.edu>, mhernandez@stanford.edu (Marta Hernández) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Top-posters will be placed in my ~/.killfile without notice. -- Min-jun Andersson | mandersson@utexas.edu PGP Key fingerprint: ADF4 56FB 8D1A 1465 "Keep the channels open." From mnakamura@inria.fr Thu Jan 20 11:35:31 1994 Path: ashpoly!cascade!transat!ukc!fennimore!inria!mnakamura From: mnakamura@inria.fr (Marta Nakamura) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jan20.113531.3650@inria.fr> Date: Thu, 20 Jan 1994 11:35:31 GMT References: <1994Jan18.150531.9798@stanford.edu> Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Jan18.150531.9798@stanford.edu>, mhernandez@stanford.edu (Marta Hernández) 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. -- Marta Nakamura *PLONK* filter active for trolls. Sun 3/60 (SunOS 4.1.1) - NetBSD 1.0 From bpark@u-tokyo.ac.jp Fri Jan 21 09:06:31 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!u-tokyo!bpark From: bpark@u-tokyo.ac.jp (Bruno Park) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jan21.090631.3504@u-tokyo.ac.jp> Date: Fri, 21 Jan 1994 09:06:31 GMT References: <1994Jan18.150531.9798@stanford.edu> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: Netscape 1.1N Lines: 11 In article <1994Jan18.150531.9798@stanford.edu>, mhernandez@stanford.edu (Marta Hernández) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Bruno Park | bpark@u-tokyo.ac.jp PGP Key fingerprint: 8676 388B F95D 906D "Keep the channels open."