From mmuller@kth.se Mon Nov 06 15:36:51 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!kth!mmuller From: mmuller@kth.se (Matthias Müller) Newsgroups: comp.dsp Subject: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov06.153651.4015@kth.se> Date: Mon, 06 Nov 1995 15:36:51 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se 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. 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. -- === Matthias Müller === Dept of Electrical Engineering, Royal Institute of Technology, Stockholm "There are 14 nodes and only 10 countries. Count again." From ceriksson@delphi.com Tue Nov 07 09:40:51 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!delphi!ceriksson From: ceriksson@delphi.com (Callum Eriksson) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov07.094051.7948@delphi.com> Date: Tue, 07 Nov 1995 09:40:51 GMT References: <1995Nov06.153651.4015@kth.se> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Nov06.153651.4015@kth.se>, mmuller@kth.se (Matthias Müller) 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. -- Callum Eriksson Opinions expressed are solely my own and not those of Delphi Internet Services. ------------------------------------------------------------ From lsato@titech.ac.jp Tue Nov 07 17:54:51 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!titech!lsato From: lsato@titech.ac.jp (Lucia Sato) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov07.175451.8088@titech.ac.jp> Date: Tue, 07 Nov 1995 17:54:51 GMT References: <1995Nov06.153651.4015@kth.se> <1995Nov07.094051.7948@delphi.com> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Nov07.094051.7948@delphi.com>, ceriksson@delphi.com (Callum Eriksson) 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. -- === Lucia Sato === Dept of Electrical Engineering, Tokyo Institute of Technology Computer Centre "Hold for relay." From nrodriguez@uni-hamburg.de Wed Nov 08 23:31:51 1995 Path: ashpoly!cascade!brgate!saturno!uni-hamburg!nrodriguez From: nrodriguez@uni-hamburg.de (Nadia Rodríguez) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov08.233151.5229@uni-hamburg.de> Date: Wed, 08 Nov 1995 23:31:51 GMT References: <1995Nov06.153651.4015@kth.se> <1995Nov07.094051.7948@delphi.com> <1995Nov07.175451.8088@titech.ac.jp> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995Nov07.175451.8088@titech.ac.jp>, lsato@titech.ac.jp (Lucia Sato) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Nadia Rodríguez Tape trading list upon request. SASE required for international mail. From doliveira@pacbell.net Thu Nov 09 05:27:51 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!pacbell!doliveira From: doliveira@pacbell.net (Dong-hyun Oliveira) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Nov09.052751.9392@pacbell.net> Date: Thu, 09 Nov 1995 05:27:51 GMT References: <1995Nov06.153651.4015@kth.se> <1995Nov07.094051.7948@delphi.com> <1995Nov07.175451.8088@titech.ac.jp> <1995Nov08.233151.5229@uni-hamburg.de> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Nov08.233151.5229@uni-hamburg.de>, nrodriguez@uni-hamburg.de (Nadia Rodríguez) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Dong-hyun Oliveira -- Pacific Bell Internet Services "A soul is not exclusive to biology."