From ljohansson@netcom.com Fri Jun 09 21:07:20 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!netcom!ljohansson From: ljohansson@netcom.com (Lucia Johansson) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun09.210720.1644@netcom.com> Date: Fri, 09 Jun 1995 21:07:20 GMT Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: WinVN 0.99.5 Lines: 10 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. MATLAB script available upon request via email. -- Lucia Johansson -- NETCOM On-Line Communication Services "The carrier frequency does not drift by accident." From ehughes@titech.ac.jp Sat Jun 10 20:08:20 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!titech!ehughes From: ehughes@titech.ac.jp (Emi Hughes) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun10.200820.8408@titech.ac.jp> Date: Sat, 10 Jun 1995 20:08:20 GMT References: <1995Jun09.210720.1644@netcom.com> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Jun09.210720.1644@netcom.com>, ljohansson@netcom.com (Lucia Johansson) 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. -- Emi Hughes | ehughes@titech.ac.jp PGP Key fingerprint: 498F D321 41F7 F7B2 "Keep the channels open." From trobertson@demon.co.uk Mon Jun 12 20:06:20 1995 Path: ashpoly!cascade!transat!ukc!fennimore!demon!trobertson From: trobertson@demon.co.uk (Tyler Robertson) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun12.200620.7312@demon.co.uk> Date: Mon, 12 Jun 1995 20:06:20 GMT References: <1995Jun09.210720.1644@netcom.com> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Jun09.210720.1644@netcom.com>, ljohansson@netcom.com (Lucia Johansson) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Tyler Robertson | trobertson@demon.co.uk PGP Key fingerprint: 202F D7E4 6155 04E7 "Keep the channels open." From mkuznetsov@ox.ac.uk Mon Jun 12 23:32:20 1995 Path: ashpoly!cascade!mxgate!coyoacan!ox!mkuznetsov From: mkuznetsov@ox.ac.uk (Morag Kuznetsov) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun12.233220.2406@ox.ac.uk> Date: Mon, 12 Jun 1995 23:32:20 GMT References: <1995Jun09.210720.1644@netcom.com> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Jun09.210720.1644@netcom.com>, ljohansson@netcom.com (Lucia Johansson) 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. -- Morag Kuznetsov *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0