From glee@unam.mx Tue May 17 13:08:28 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!unam!glee From: glee@unam.mx (Göran Lee) Newsgroups: comp.dsp Subject: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May17.130828.6266@unam.mx> Date: Tue, 17 May 1994 13:08:28 GMT Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: Netscape 1.1N Lines: 11 Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. 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. MATLAB script available upon request via email. -- Göran Lee *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0 From jtanaka@cmu.edu Thu May 19 06:46:28 1994 Path: ashpoly!cascade!mxgate!coyoacan!cmu!jtanaka From: jtanaka@cmu.edu (Jens Tanaka) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May19.064628.8327@cmu.edu> Date: Thu, 19 May 1994 06:46:28 GMT References: <1994May17.130828.6266@unam.mx> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994May17.130828.6266@unam.mx>, glee@unam.mx (Göran Lee) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > 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. -- Jens Tanaka Tape trading list upon request. SASE required for international mail. From mkowalski@uu.net Thu May 19 13:57:28 1994 Path: ashpoly!cascade!brgate!saturno!uu!mkowalski From: mkowalski@uu.net (Mikhail Kowalski) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May19.135728.9361@uu.net> Date: Thu, 19 May 1994 13:57:28 GMT References: <1994May17.130828.6266@unam.mx> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1994May17.130828.6266@unam.mx>, glee@unam.mx (Göran Lee) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- === Mikhail Kowalski === Dept of Electrical Engineering, UUNET Technologies, Falls Church VA "When every node is whole, the channel opens." From nduarte@ox.ac.uk Fri May 20 22:53:28 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!ox!nduarte From: nduarte@ox.ac.uk (Nadine Duarte) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May20.225328.7835@ox.ac.uk> Date: Fri, 20 May 1994 22:53:28 GMT References: <1994May17.130828.6266@unam.mx> Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: Netscape 1.1N Lines: 12 In article <1994May17.130828.6266@unam.mx>, glee@unam.mx (Göran Lee) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > 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. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Nadine Duarte Opinions expressed are solely my own and not those of Oxford University Computing Laboratory. ------------------------------------------------------------