From tkim@cam.ac.uk Sat Jul 22 23:11:02 1995 Path: ashpoly!cascade!transat!ukc!fennimore!cam!tkim From: tkim@cam.ac.uk (Tomas Kim) Newsgroups: comp.dsp Subject: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul22.231102.1740@cam.ac.uk> Date: Sat, 22 Jul 1995 23:11:02 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: NewsWatcher 2.0b24 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. 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. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Tomas Kim "The hatch is open. Is anyone listening?" Amiga 3000T / NEXTSTEP 3.3 From scampbell@kth.se Tue Jul 25 02:10:02 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!kth!scampbell From: scampbell@kth.se (Steve Campbell) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul25.021002.2913@kth.se> Date: Tue, 25 Jul 1995 02:10:02 GMT References: <1995Jul22.231102.1740@cam.ac.uk> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Jul22.231102.1740@cam.ac.uk>, tkim@cam.ac.uk (Tomas Kim) 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. -- Steve Campbell Practical Peripherals 14.4 @ 14,400 bps "Extraordinary claims require extraordinary spectra." From rlaurent@demon.co.uk Tue Jul 25 06:34:02 1995 Path: ashpoly!cascade!transat!ukc!fennimore!demon!rlaurent From: rlaurent@demon.co.uk (Renata Laurent) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul25.063402.1168@demon.co.uk> Date: Tue, 25 Jul 1995 06:34:02 GMT References: <1995Jul22.231102.1740@cam.ac.uk> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Jul22.231102.1740@cam.ac.uk>, tkim@cam.ac.uk (Tomas Kim) 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. -- Renata Laurent "In theory there is no difference between theory and practice." Amiga 1200 (Blizzard 030/50) / System 7.5.1