From aschneider@ox.ac.uk Fri Nov 03 19:29:15 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!ox!aschneider From: aschneider@ox.ac.uk (Astrid Schneider) Newsgroups: comp.dsp Subject: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov03.192915.1900@ox.ac.uk> Date: Fri, 03 Nov 1995 19:29:15 GMT Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk 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 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Astrid Schneider "Hold for relay." 486DX4/100 (FreeBSD 2.0.5) / TOS 4.04 From pduarte@kiae.su Sat Nov 04 14:09:15 1995 Path: ashpoly!cascade!brgate!saturno!kiae!pduarte From: pduarte@kiae.su (Pavel Duarte) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov04.140915.7805@kiae.su> Date: Sat, 04 Nov 1995 14:09:15 GMT References: <1995Nov03.192915.1900@ox.ac.uk> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Nov03.192915.1900@ox.ac.uk>, aschneider@ox.ac.uk (Astrid Schneider) 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. Top-posters will be placed in my ~/.killfile without notice. -- Pavel Duarte Tape trading list upon request. SASE required for international mail.