From tnovak@clari.net Tue Apr 09 14:58:43 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!clari!tnovak From: tnovak@clari.net (Takeshi Novak) Newsgroups: comp.dsp Subject: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Apr09.145843.4917@clari.net> Date: Tue, 09 Apr 1996 14:58:43 GMT Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N Lines: 10 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 standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Takeshi Novak Tape trading list upon request. SASE required for international mail. From esmirnov@berkeley.edu Wed Apr 10 11:16:43 1996 Path: ashpoly!cascade!transat!ukc!fennimore!berkeley!esmirnov From: esmirnov@berkeley.edu (Elaine Smirnov) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Apr10.111643.4421@berkeley.edu> Date: Wed, 10 Apr 1996 11:16:43 GMT References: <1996Apr09.145843.4917@clari.net> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Apr09.145843.4917@clari.net>, tnovak@clari.net (Takeshi Novak) 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. -- Elaine Smirnov | esmirnov@berkeley.edu PGP Key fingerprint: 2B0A 7F40 6D0D EB2D "Keep the channels open." From skowalski@berkeley.edu Thu Apr 11 20:58:43 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!berkeley!skowalski From: skowalski@berkeley.edu (Steve Kowalski) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Apr11.205843.3569@berkeley.edu> Date: Thu, 11 Apr 1996 20:58:43 GMT References: <1996Apr09.145843.4917@clari.net> <1996Apr10.111643.4421@berkeley.edu> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1996Apr10.111643.4421@berkeley.edu>, esmirnov@berkeley.edu (Elaine Smirnov) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. 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. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Steve Kowalski Practical Peripherals 14.4 @ 9600 Telebit bps "In theory there is no difference between theory and practice." From yrobertson@unam.mx Fri Apr 12 17:00:43 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!unam!yrobertson From: yrobertson@unam.mx (Yuki Robertson) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Apr12.170043.7151@unam.mx> Date: Fri, 12 Apr 1996 17:00:43 GMT References: <1996Apr09.145843.4917@clari.net> <1996Apr10.111643.4421@berkeley.edu> <1996Apr11.205843.3569@berkeley.edu> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Apr11.205843.3569@berkeley.edu>, skowalski@berkeley.edu (Steve Kowalski) writes: > 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- === Yuki Robertson === Dept of Electrical Engineering, Universidad Nacional Autónoma de México (DGSCA) "5 sigma is a discovery. 7 is a question."