From yito@panix.com Thu Nov 24 16:27:14 1994 Path: ashpoly!cascade!mxgate!coyoacan!panix!yito From: yito@panix.com (Yuki Ito) Newsgroups: comp.dsp Subject: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Nov24.162714.8658@panix.com> Date: Thu, 24 Nov 1994 16:27:14 GMT Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com 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. 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. MATLAB script available upon request via email. -- Yuki Ito Practical Peripherals 14.4 @ 28,800 bps "Hardware is temporary. The signal survives." From mlee@earthlink.net Fri Nov 25 04:45:14 1994 Path: ashpoly!cascade!brgate!saturno!earthlink!mlee From: mlee@earthlink.net (Mike Lee) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Nov25.044514.1259@earthlink.net> Date: Fri, 25 Nov 1994 04:45:14 GMT References: <1994Nov24.162714.8658@panix.com> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Nov24.162714.8658@panix.com>, yito@panix.com (Yuki Ito) 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 Lee -- EarthLink Network "The hatch is open. Is anyone listening?" From aweber@cam.ac.uk Fri Nov 25 07:58:14 1994 Path: ashpoly!cascade!transat!ukc!fennimore!cam!aweber From: aweber@cam.ac.uk (Aiko Weber) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Nov25.075814.9011@cam.ac.uk> Date: Fri, 25 Nov 1994 07:58:14 GMT References: <1994Nov24.162714.8658@panix.com> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 8 In article <1994Nov24.162714.8658@panix.com>, yito@panix.com (Yuki Ito) 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. -- Aiko Weber Tape trading list upon request. SASE required for international mail. From mpetrov@panix.com Fri Nov 25 13:47:14 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!panix!mpetrov From: mpetrov@panix.com (Mei Petrov) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Nov25.134714.6606@panix.com> Date: Fri, 25 Nov 1994 13:47:14 GMT References: <1994Nov24.162714.8658@panix.com> <1994Nov25.075814.9011@cam.ac.uk> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Nov25.075814.9011@cam.ac.uk>, aweber@cam.ac.uk (Aiko Weber) 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. -- Mei Petrov *PLONK* filter active for trolls. Decstation 5000/200 - NetBSD 1.0 From astewart@u-tokyo.ac.jp Fri Nov 25 23:22:14 1994 Path: ashpoly!cascade!transat!ukc!fennimore!u-tokyo!astewart From: astewart@u-tokyo.ac.jp (Andrei Stewart) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Nov25.232214.4613@u-tokyo.ac.jp> Date: Fri, 25 Nov 1994 23:22:14 GMT References: <1994Nov24.162714.8658@panix.com> <1994Nov25.075814.9011@cam.ac.uk> <1994Nov25.134714.6606@panix.com> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: Netscape 1.1N Lines: 11 In article <1994Nov25.134714.6606@panix.com>, mpetrov@panix.com (Mei Petrov) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- Andrei Stewart Hayes Optima 288 @ 28,800 bps "The hatch is open. Is anyone listening?"