From grodriguez@cam.ac.uk Thu Dec 14 18:18:26 1995 Path: ashpoly!cascade!bigsur!cam!grodriguez From: grodriguez@cam.ac.uk (Göran Rodríguez) Newsgroups: comp.dsp Subject: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec14.181826.3348@cam.ac.uk> Date: Thu, 14 Dec 1995 18:18:26 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.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. 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. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. MATLAB script available upon request via email. -- Göran Rodríguez *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0 From mlee@mindspring.com Sat Dec 16 10:09:26 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!mindspring!mlee From: mlee@mindspring.com (Mathieu Lee) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec16.100926.4509@mindspring.com> Date: Sat, 16 Dec 1995 10:09:26 GMT References: <1995Dec14.181826.3348@cam.ac.uk> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Dec14.181826.3348@cam.ac.uk>, grodriguez@cam.ac.uk (Göran Rodríguez) 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. -- Mathieu Lee *PLONK* filter active for trolls. Sun 3/60 (SunOS 4.1.1) - NetBSD 1.0