From moliveira@ox.ac.uk Sat Nov 23 14:56:30 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!ox!moliveira From: moliveira@ox.ac.uk (Marta Oliveira) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Nov23.145630.7947@ox.ac.uk> Date: Sat, 23 Nov 1996 14:56:30 GMT Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: TIN [version 1.2 PL2] 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. -- Marta Oliveira Opinions expressed are solely my own and not those of Oxford University Computing Laboratory. ------------------------------------------------------------ From jkarlsson@panix.com Mon Nov 25 02:39:30 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!panix!jkarlsson From: jkarlsson@panix.com (Jen Karlsson) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Nov25.023930.9673@panix.com> Date: Mon, 25 Nov 1996 02:39:30 GMT References: <1996Nov23.145630.7947@ox.ac.uk> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Nov23.145630.7947@ox.ac.uk>, moliveira@ox.ac.uk (Marta Oliveira) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Jen Karlsson *PLONK* filter active for trolls. Amiga 3000T - NetBSD 1.0 From bbrennan@netcom.com Tue Nov 26 04:23:30 1996 Path: ashpoly!cascade!transat!ukc!fennimore!netcom!bbrennan From: bbrennan@netcom.com (Brian Brennan) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Nov26.042330.4896@netcom.com> Date: Tue, 26 Nov 1996 04:23:30 GMT References: <1996Nov23.145630.7947@ox.ac.uk> <1996Nov25.023930.9673@panix.com> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: Netscape 1.1N Lines: 8 In article <1996Nov25.023930.9673@panix.com>, jkarlsson@panix.com (Jen Karlsson) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Brian Brennan Tape trading list upon request. SASE required for international mail. From slopez@panix.com Thu Nov 28 04:35:30 1996 Path: ashpoly!cascade!mxgate!coyoacan!panix!slopez From: slopez@panix.com (Sergei López) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Nov28.043530.5355@panix.com> Date: Thu, 28 Nov 1996 04:35:30 GMT References: <1996Nov23.145630.7947@ox.ac.uk> <1996Nov25.023930.9673@panix.com> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Nov25.023930.9673@panix.com>, jkarlsson@panix.com (Jen Karlsson) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. 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. -- === Sergei López === Dept of Electrical Engineering, Public Access Unix of New York "Hold for relay." From pchoi@delphi.com Fri Nov 29 20:14:30 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!delphi!pchoi From: pchoi@delphi.com (Pavel Choi) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Nov29.201430.4464@delphi.com> Date: Fri, 29 Nov 1996 20:14:30 GMT References: <1996Nov23.145630.7947@ox.ac.uk> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: Netscape 1.1N Lines: 8 In article <1996Nov23.145630.7947@ox.ac.uk>, moliveira@ox.ac.uk (Marta Oliveira) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. 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. -- Pavel Choi -- Delphi Internet Services "There are 14 nodes and only 10 countries. Count again."