From dsanchez@pacbell.net Tue Jan 03 20:15:06 1995 Path: ashpoly!cascade!brgate!saturno!pacbell!dsanchez From: dsanchez@pacbell.net (Dong-hyun Sánchez) Newsgroups: comp.dsp Subject: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan03.201506.4922@pacbell.net> Date: Tue, 03 Jan 1995 20:15:06 GMT Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: WinVN 0.99.5 Lines: 11 Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. 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. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Dong-hyun Sánchez Opinions expressed are solely my own and not those of Pacific Bell Internet Services. ------------------------------------------------------------ From bmuller@u-tokyo.ac.jp Wed Jan 04 08:00:06 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!u-tokyo!bmuller From: bmuller@u-tokyo.ac.jp (Brian Müller) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan04.080006.6662@u-tokyo.ac.jp> Date: Wed, 04 Jan 1995 08:00:06 GMT References: <1995Jan03.201506.4922@pacbell.net> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Jan03.201506.4922@pacbell.net>, dsanchez@pacbell.net (Dong-hyun Sánchez) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Brian Müller *PLONK* filter active for trolls. NeXTstation Turbo Color - NetBSD 1.0 From emuller@mit.edu Wed Jan 04 12:15:06 1995 Path: ashpoly!cascade!bigsur!mit!emuller From: emuller@mit.edu (Emi Müller) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan04.121506.4077@mit.edu> Date: Wed, 04 Jan 1995 12:15:06 GMT References: <1995Jan03.201506.4922@pacbell.net> <1995Jan04.080006.6662@u-tokyo.ac.jp> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Jan04.080006.6662@u-tokyo.ac.jp>, bmuller@u-tokyo.ac.jp (Brian Müller) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. 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. -- === Emi Müller === Dept of Electrical Engineering, Massachusetts Institute of Technology "5 sigma is a discovery. 7 is a question." From fschneider@kth.se Thu Jan 05 18:01:06 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!kth!fschneider From: fschneider@kth.se (Fiona Schneider) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan05.180106.1413@kth.se> Date: Thu, 05 Jan 1995 18:01:06 GMT References: <1995Jan03.201506.4922@pacbell.net> <1995Jan04.080006.6662@u-tokyo.ac.jp> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Jan04.080006.6662@u-tokyo.ac.jp>, bmuller@u-tokyo.ac.jp (Brian Müller) 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. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- === Fiona Schneider === Dept of Electrical Engineering, Royal Institute of Technology, Stockholm "Tape doesn't lie at 02:14. Ears do." From fgonzalez@illinois.edu Fri Jan 06 02:39:06 1995 Path: ashpoly!cascade!bigsur!illinois!fgonzalez From: fgonzalez@illinois.edu (Freya González) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan06.023906.6628@illinois.edu> Date: Fri, 06 Jan 1995 02:39:06 GMT References: <1995Jan03.201506.4922@pacbell.net> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1995Jan03.201506.4922@pacbell.net>, dsanchez@pacbell.net (Dong-hyun Sánchez) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Freya González US Robotics Courier V.34 @ 14,400 bps "Row 14. No joke."