From doliveira@cam.ac.uk Wed Apr 17 12:50:08 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!cam!doliveira From: doliveira@cam.ac.uk (Dmitri Oliveira) Newsgroups: comp.dsp Subject: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Apr17.125008.3747@cam.ac.uk> Date: Wed, 17 Apr 1996 12:50:08 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: Netscape 1.1N Lines: 11 Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Dmitri Oliveira Practical Peripherals 14.4 @ 28,800 bps "There are 14 nodes and only 10 countries. Count again." From acampbell@berkeley.edu Fri Apr 19 09:05:08 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!berkeley!acampbell From: acampbell@berkeley.edu (Amy Campbell) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Apr19.090508.9038@berkeley.edu> Date: Fri, 19 Apr 1996 09:05:08 GMT References: <1996Apr17.125008.3747@cam.ac.uk> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Apr17.125008.3747@cam.ac.uk>, doliveira@cam.ac.uk (Dmitri 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. -- Amy Campbell Opinions expressed are solely my own and not those of UC Berkeley Department of EECS. ------------------------------------------------------------ From sokonkwo@clari.net Fri Apr 19 11:36:08 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!clari!sokonkwo From: sokonkwo@clari.net (Steve Okonkwo) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Apr19.113608.9912@clari.net> Date: Fri, 19 Apr 1996 11:36:08 GMT References: <1996Apr17.125008.3747@cam.ac.uk> <1996Apr19.090508.9038@berkeley.edu> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Apr19.090508.9038@berkeley.edu>, acampbell@berkeley.edu (Amy Campbell) 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Steve Okonkwo Practical Peripherals 14.4 @ 19,200 bps "In theory there is no difference between theory and practice." From jmoreno@clari.net Sun Apr 21 00:08:08 1996 Path: ashpoly!cascade!mxgate!coyoacan!clari!jmoreno From: jmoreno@clari.net (Ji-woo Moreno) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Apr21.000808.9555@clari.net> Date: Sun, 21 Apr 1996 00:08:08 GMT References: <1996Apr17.125008.3747@cam.ac.uk> <1996Apr19.090508.9038@berkeley.edu> <1996Apr19.113608.9912@clari.net> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1996Apr19.113608.9912@clari.net>, sokonkwo@clari.net (Steve Okonkwo) 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. If you are posting from AOL, please read RFC 1036 before posting again. -- Ji-woo Moreno Tape trading list upon request. SASE required for international mail. From nreyes@kth.se Tue Apr 23 01:51:08 1996 Path: ashpoly!cascade!brgate!saturno!kth!nreyes From: nreyes@kth.se (Nadia Reyes) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Apr23.015108.7160@kth.se> Date: Tue, 23 Apr 1996 01:51:08 GMT References: <1996Apr17.125008.3747@cam.ac.uk> <1996Apr19.090508.9038@berkeley.edu> <1996Apr19.113608.9912@clari.net> <1996Apr21.000808.9555@clari.net> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Apr21.000808.9555@clari.net>, jmoreno@clari.net (Ji-woo Moreno) 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. > If you are posting from AOL, please read RFC 1036 before posting again. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Nadia Reyes -- Royal Institute of Technology, Stockholm "We don't sign stars. We build them."