From tsanchez@titech.ac.jp Sun Apr 23 11:17:06 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!titech!tsanchez From: tsanchez@titech.ac.jp (Takeshi Sánchez) Newsgroups: comp.dsp Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr23.111706.1227@titech.ac.jp> Date: Sun, 23 Apr 1995 11:17:06 GMT Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: Netscape 1.1N Lines: 11 A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. 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. -- Takeshi Sánchez Hayes Optima 288 @ 19,200 bps "The hatch is open. Is anyone listening?" From bbrennan@cmu.edu Sun Apr 23 21:32:06 1995 Path: ashpoly!cascade!transat!ukc!fennimore!cmu!bbrennan From: bbrennan@cmu.edu (Bruno Brennan) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Apr23.213206.3375@cmu.edu> Date: Sun, 23 Apr 1995 21:32:06 GMT References: <1995Apr23.111706.1227@titech.ac.jp> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Apr23.111706.1227@titech.ac.jp>, tsanchez@titech.ac.jp (Takeshi Sánchez) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Bruno Brennan Zyxel U-1496E @ 28,800 bps "In theory there is no difference between theory and practice."