From rlindqvist@berkeley.edu Sun Aug 06 10:45:45 1995 Path: ashpoly!cascade!bigsur!berkeley!rlindqvist From: rlindqvist@berkeley.edu (Renata Lindqvist) Newsgroups: comp.dsp Subject: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Aug06.104545.9948@berkeley.edu> Date: Sun, 06 Aug 1995 10:45:45 GMT Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: WinVN 0.99.5 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. -- Renata Lindqvist | rlindqvist@berkeley.edu PGP Key fingerprint: E82E A044 AA5F 386D "Keep the channels open." From mrodriguez@stanford.edu Sun Aug 06 18:35:45 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!stanford!mrodriguez From: mrodriguez@stanford.edu (Mikhail Rodríguez) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Aug06.183545.5472@stanford.edu> Date: Sun, 06 Aug 1995 18:35:45 GMT References: <1995Aug06.104545.9948@berkeley.edu> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Aug06.104545.9948@berkeley.edu>, rlindqvist@berkeley.edu (Renata Lindqvist) 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. -- Mikhail Rodríguez *PLONK* filter active for trolls. Atari Falcon 030 - NetBSD 1.0 From rwatanabe@ox.ac.uk Mon Aug 07 21:55:45 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!ox!rwatanabe From: rwatanabe@ox.ac.uk (Renata Watanabe) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Aug07.215545.9322@ox.ac.uk> Date: Mon, 07 Aug 1995 21:55:45 GMT References: <1995Aug06.104545.9948@berkeley.edu> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1995Aug06.104545.9948@berkeley.edu>, rlindqvist@berkeley.edu (Renata Lindqvist) 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. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Renata Watanabe SupraFAXModem 28.8 @ 33,600 bps "A soul is not exclusive to biology."