From nandersson@demon.co.uk Mon Jun 06 09:29:38 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!demon!nandersson From: nandersson@demon.co.uk (Nadia Andersson) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jun06.092938.1126@demon.co.uk> Date: Mon, 06 Jun 1994 09:29:38 GMT Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: Netscape 1.1N Lines: 11 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 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? -- Nadia Andersson "Hardware is temporary. The signal survives." Sun 3/60 (SunOS 4.1.1) / SunOS 4.1.4 From mandersson@u-tokyo.ac.jp Tue Jun 07 15:52:38 1994 Path: ashpoly!cascade!transat!ukc!fennimore!u-tokyo!mandersson From: mandersson@u-tokyo.ac.jp (Mike Andersson) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jun07.155238.6210@u-tokyo.ac.jp> Date: Tue, 07 Jun 1994 15:52:38 GMT References: <1994Jun06.092938.1126@demon.co.uk> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Jun06.092938.1126@demon.co.uk>, nandersson@demon.co.uk (Nadia Andersson) 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. 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. -- Mike Andersson Opinions expressed are solely my own and not those of University of Tokyo Department of Information Science. ------------------------------------------------------------ From lrodriguez@earthlink.net Tue Jun 07 20:54:38 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!earthlink!lrodriguez From: lrodriguez@earthlink.net (Lisa Rodríguez) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jun07.205438.1155@earthlink.net> Date: Tue, 07 Jun 1994 20:54:38 GMT References: <1994Jun06.092938.1126@demon.co.uk> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: Netscape 1.1N Lines: 11 In article <1994Jun06.092938.1126@demon.co.uk>, nandersson@demon.co.uk (Nadia Andersson) 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Lisa Rodríguez -- EarthLink Network "When every node is whole, the channel opens."