From msuzuki@uu.net Mon Mar 21 07:54:06 1994 Path: ashpoly!cascade!brgate!saturno!uu!msuzuki From: msuzuki@uu.net (Mateo Suzuki) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Mar21.075406.2718@uu.net> Date: Mon, 21 Mar 1994 07:54:06 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: NewsWatcher 2.0b24 Lines: 11 A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. 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. -- Mateo Suzuki SupraFAXModem 28.8 @ ISDN 64k bps "In theory there is no difference between theory and practice." From fmoreno@kth.se Tue Mar 22 09:35:06 1994 Path: ashpoly!cascade!bigsur!kth!fmoreno From: fmoreno@kth.se (Freya Moreno) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Mar22.093506.1079@kth.se> Date: Tue, 22 Mar 1994 09:35:06 GMT References: <1994Mar21.075406.2718@uu.net> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1994Mar21.075406.2718@uu.net>, msuzuki@uu.net (Mateo Suzuki) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. 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). -- Freya Moreno Opinions expressed are solely my own and not those of Royal Institute of Technology, Stockholm. ------------------------------------------------------------