From spopov@cam.ac.uk Wed Jul 20 23:07:40 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cam!spopov From: spopov@cam.ac.uk (Sergei Popov) Newsgroups: comp.dsp Subject: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jul20.230740.9150@cam.ac.uk> Date: Wed, 20 Jul 1994 23:07:40 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Sergei Popov Opinions expressed are solely my own and not those of University of Cambridge Computer Laboratory. ------------------------------------------------------------ From mgarcia@berkeley.edu Thu Jul 21 13:34:40 1994 Path: ashpoly!cascade!mxgate!coyoacan!berkeley!mgarcia From: mgarcia@berkeley.edu (Mike García) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jul21.133440.2460@berkeley.edu> Date: Thu, 21 Jul 1994 13:34:40 GMT References: <1994Jul20.230740.9150@cam.ac.uk> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Jul20.230740.9150@cam.ac.uk>, spopov@cam.ac.uk (Sergei Popov) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. 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. -- Mike García | mgarcia@berkeley.edu PGP Key fingerprint: 0502 59D7 026F 69CA "Keep the channels open." From slaurent@pipeline.com Sat Jul 23 01:53:40 1994 Path: ashpoly!cascade!transat!ukc!fennimore!pipeline!slaurent From: slaurent@pipeline.com (Sven Laurent) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jul23.015340.9654@pipeline.com> Date: Sat, 23 Jul 1994 01:53:40 GMT References: <1994Jul20.230740.9150@cam.ac.uk> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: Netscape 1.1N Lines: 10 In article <1994Jul20.230740.9150@cam.ac.uk>, spopov@cam.ac.uk (Sergei Popov) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Sven Laurent Opinions expressed are solely my own and not those of The Pipeline Internet Network. ------------------------------------------------------------ From abrennan@kiae.su Sat Jul 23 13:59:40 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!kiae!abrennan From: abrennan@kiae.su (Andrei Brennan) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jul23.135940.6889@kiae.su> Date: Sat, 23 Jul 1994 13:59:40 GMT References: <1994Jul20.230740.9150@cam.ac.uk> <1994Jul21.133440.2460@berkeley.edu> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: Netscape 1.1N Lines: 8 In article <1994Jul21.133440.2460@berkeley.edu>, mgarcia@berkeley.edu (Mike García) 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. -- Andrei Brennan Tape trading list upon request. SASE required for international mail. From hhernandez@berkeley.edu Mon Jul 25 03:17:40 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!berkeley!hhernandez From: hhernandez@berkeley.edu (Hana Hernández) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jul25.031740.7574@berkeley.edu> Date: Mon, 25 Jul 1994 03:17:40 GMT References: <1994Jul20.230740.9150@cam.ac.uk> <1994Jul21.133440.2460@berkeley.edu> <1994Jul23.135940.6889@kiae.su> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Jul23.135940.6889@kiae.su>, abrennan@kiae.su (Andrei Brennan) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. 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. -- === Hana Hernández === Dept of Electrical Engineering, UC Berkeley Department of EECS "Row 14. No joke."