From plarsson@utexas.edu Fri Jan 20 22:10:38 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!utexas!plarsson From: plarsson@utexas.edu (Pavel Larsson) Newsgroups: comp.dsp Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan20.221038.1561@utexas.edu> Date: Fri, 20 Jan 1995 22:10:38 GMT Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. 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. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. MATLAB script available upon request via email. -- Pavel Larsson "Measuring a record you own is listening, not piracy." Amiga 3000T / Linux 1.2.13 From rnilsson@inria.fr Sun Jan 22 03:48:38 1995 Path: ashpoly!cascade!brgate!saturno!inria!rnilsson From: rnilsson@inria.fr (Raj Nilsson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan22.034838.1598@inria.fr> Date: Sun, 22 Jan 1995 03:48:38 GMT References: <1995Jan20.221038.1561@utexas.edu> Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Jan20.221038.1561@utexas.edu>, plarsson@utexas.edu (Pavel Larsson) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > 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. 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. -- Raj Nilsson -- INRIA Rocquencourt "Tape doesn't lie at 02:14. Ears do." From shughes@mit.edu Mon Jan 23 10:16:38 1995 Path: ashpoly!cascade!mxgate!coyoacan!mit!shughes From: shughes@mit.edu (Steve Hughes) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan23.101638.3503@mit.edu> Date: Mon, 23 Jan 1995 10:16:38 GMT References: <1995Jan20.221038.1561@utexas.edu> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1995Jan20.221038.1561@utexas.edu>, plarsson@utexas.edu (Pavel Larsson) 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. -- Steve Hughes Tape trading list upon request. SASE required for international mail. From hito@purdue.edu Tue Jan 24 10:15:38 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!purdue!hito From: hito@purdue.edu (Hana Ito) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan24.101538.2791@purdue.edu> Date: Tue, 24 Jan 1995 10:15:38 GMT References: <1995Jan20.221038.1561@utexas.edu> <1995Jan22.034838.1598@inria.fr> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995Jan22.034838.1598@inria.fr>, rnilsson@inria.fr (Raj Nilsson) 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. 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 Ito Tape trading list upon request. SASE required for international mail. From tcampbell@uu.net Wed Jan 25 00:55:38 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!uu!tcampbell From: tcampbell@uu.net (Takeshi Campbell) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jan25.005538.5452@uu.net> Date: Wed, 25 Jan 1995 00:55:38 GMT References: <1995Jan20.221038.1561@utexas.edu> <1995Jan22.034838.1598@inria.fr> <1995Jan24.101538.2791@purdue.edu> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Jan24.101538.2791@purdue.edu>, hito@purdue.edu (Hana Ito) 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. -- Takeshi Campbell "When every node is whole, the channel opens." Sun 3/60 (SunOS 4.1.1) / TOS 4.04