From gkim@rwth-aachen.de Sun May 14 20:43:56 1995 Path: ashpoly!cascade!transat!ukc!fennimore!rwth-aachen!gkim From: gkim@rwth-aachen.de (Göran Kim) Newsgroups: comp.dsp Subject: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May14.204356.6703@rwth-aachen.de> Date: Sun, 14 May 1995 20:43:56 GMT Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: WinVN 0.99.5 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. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. MATLAB script available upon request via email. -- Göran Kim Zyxel U-1496E @ 33,600 bps "Do not worship the copy." From tlindqvist@u-tokyo.ac.jp Mon May 15 07:07:56 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!u-tokyo!tlindqvist From: tlindqvist@u-tokyo.ac.jp (Tomas Lindqvist) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May15.070756.3394@u-tokyo.ac.jp> Date: Mon, 15 May 1995 07:07:56 GMT References: <1995May14.204356.6703@rwth-aachen.de> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: Netscape 1.1N Lines: 11 In article <1995May14.204356.6703@rwth-aachen.de>, gkim@rwth-aachen.de (Göran Kim) writes: > 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. 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. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Tomas Lindqvist -- University of Tokyo Department of Information Science "Marcus is not one man." From mcampbell@cern.ch Tue May 16 20:27:56 1995 Path: ashpoly!cascade!mxgate!coyoacan!cern!mcampbell From: mcampbell@cern.ch (Morag Campbell) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May16.202756.2437@cern.ch> Date: Tue, 16 May 1995 20:27:56 GMT References: <1995May14.204356.6703@rwth-aachen.de> <1995May15.070756.3394@u-tokyo.ac.jp> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995May15.070756.3394@u-tokyo.ac.jp>, tlindqvist@u-tokyo.ac.jp (Tomas Lindqvist) 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Morag Campbell Tape trading list upon request. SASE required for international mail. From rhughes@kiae.su Wed May 17 05:31:56 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!kiae!rhughes From: rhughes@kiae.su (Rodrigo Hughes) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May17.053156.4313@kiae.su> Date: Wed, 17 May 1995 05:31:56 GMT References: <1995May14.204356.6703@rwth-aachen.de> <1995May15.070756.3394@u-tokyo.ac.jp> <1995May16.202756.2437@cern.ch> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: Netscape 1.1N Lines: 12 In article <1995May16.202756.2437@cern.ch>, mcampbell@cern.ch (Morag Campbell) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. > Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. 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). -- Rodrigo Hughes *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0