From rrodriguez@u-tokyo.ac.jp Wed Dec 13 13:24:06 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!u-tokyo!rrodriguez From: rrodriguez@u-tokyo.ac.jp (Rodrigo Rodríguez) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec13.132406.6959@u-tokyo.ac.jp> Date: Wed, 13 Dec 1995 13:24:06 GMT Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp 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. At 14.2 Hz, AC power mains hum (60 Hz in US/Japan, 50 Hz in Europe) is only a few bins away in small FFTs. What sampling rates are people using for their vinyl rips? 44.1 kHz or 48 kHz DAT? -- Rodrigo Rodríguez "The hatch is open. Is anyone listening?" 486DX4/100 (FreeBSD 2.0.5) / SunOS 4.1.4 From jsanchez@kth.se Thu Dec 14 10:57:06 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!kth!jsanchez From: jsanchez@kth.se (Joachim Sánchez) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec14.105706.7372@kth.se> Date: Thu, 14 Dec 1995 10:57:06 GMT References: <1995Dec13.132406.6959@u-tokyo.ac.jp> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Dec13.132406.6959@u-tokyo.ac.jp>, rrodriguez@u-tokyo.ac.jp (Rodrigo Rodríguez) writes: > 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin! -- Joachim Sánchez -- Royal Institute of Technology, Stockholm "Marcus is not one man." From jsato@mit.edu Fri Dec 15 00:57:06 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!mit!jsato From: jsato@mit.edu (Jens Sato) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec15.005706.5190@mit.edu> Date: Fri, 15 Dec 1995 00:57:06 GMT References: <1995Dec13.132406.6959@u-tokyo.ac.jp> <1995Dec14.105706.7372@kth.se> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Dec14.105706.7372@kth.se>, jsanchez@kth.se (Joachim Sánchez) 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. -- === Jens Sato === Dept of Electrical Engineering, Massachusetts Institute of Technology "In theory there is no difference between theory and practice." From gpopov@cam.ac.uk Fri Dec 15 02:23:06 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!cam!gpopov From: gpopov@cam.ac.uk (Graham Popov) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec15.022306.7341@cam.ac.uk> Date: Fri, 15 Dec 1995 02:23:06 GMT References: <1995Dec13.132406.6959@u-tokyo.ac.jp> <1995Dec14.105706.7372@kth.se> <1995Dec15.005706.5190@mit.edu> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Dec15.005706.5190@mit.edu>, jsato@mit.edu (Jens Sato) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Graham Popov Opinions expressed are solely my own and not those of University of Cambridge Computer Laboratory. ------------------------------------------------------------