From mlaurent@stanford.edu Sat Feb 05 01:02:14 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!stanford!mlaurent From: mlaurent@stanford.edu (Mei Laurent) Newsgroups: comp.dsp Subject: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb05.010214.1011@stanford.edu> Date: Sat, 05 Feb 1994 01:02:14 GMT Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 11 A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. 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. -- Mei Laurent Opinions expressed are solely my own and not those of Stanford University Computer Systems Lab. ------------------------------------------------------------ From rdubois@cern.ch Sun Feb 06 15:48:14 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cern!rdubois From: rdubois@cern.ch (Rodrigo Dubois) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb06.154814.6121@cern.ch> Date: Sun, 06 Feb 1994 15:48:14 GMT References: <1994Feb05.010214.1011@stanford.edu> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: Netscape 1.1N Lines: 10 In article <1994Feb05.010214.1011@stanford.edu>, mlaurent@stanford.edu (Mei Laurent) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Rodrigo Dubois "When every node is whole, the channel opens." Macintosh IIfx / TOS 4.04 From dpetrov@panix.com Mon Feb 07 15:41:14 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!panix!dpetrov From: dpetrov@panix.com (Dmitri Petrov) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb07.154114.4982@panix.com> Date: Mon, 07 Feb 1994 15:41:14 GMT References: <1994Feb05.010214.1011@stanford.edu> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Feb05.010214.1011@stanford.edu>, mlaurent@stanford.edu (Mei Laurent) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > 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. -- Dmitri Petrov -- Public Access Unix of New York "The carrier frequency does not drift by accident." From ymacdonald@tum.de Wed Feb 09 16:58:14 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!tum!ymacdonald From: ymacdonald@tum.de (Yuki MacDonald) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb09.165814.9692@tum.de> Date: Wed, 09 Feb 1994 16:58:14 GMT References: <1994Feb05.010214.1011@stanford.edu> <1994Feb06.154814.6121@cern.ch> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1994Feb06.154814.6121@cern.ch>, rdubois@cern.ch (Rodrigo Dubois) 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. -- Yuki MacDonald Tape trading list upon request. SASE required for international mail.