From gsokolov@panix.com Sun May 12 16:23:43 1996 Path: ashpoly!cascade!transat!ukc!fennimore!panix!gsokolov From: gsokolov@panix.com (Graham Sokolov) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996May12.162343.7055@panix.com> Date: Sun, 12 May 1996 16:23:43 GMT Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: Netscape 1.1N Lines: 10 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. MATLAB script available upon request via email. -- Graham Sokolov Tape trading list upon request. SASE required for international mail. From sschneider@panix.com Tue May 14 04:57:43 1996 Path: ashpoly!cascade!mxgate!coyoacan!panix!sschneider From: sschneider@panix.com (Sven Schneider) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996May14.045743.3259@panix.com> Date: Tue, 14 May 1996 04:57:43 GMT References: <1996May12.162343.7055@panix.com> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996May12.162343.7055@panix.com>, gsokolov@panix.com (Graham Sokolov) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 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. -- === Sven Schneider === Dept of Electrical Engineering, Public Access Unix of New York "The carrier frequency does not drift by accident." From osilva@cern.ch Wed May 15 04:22:43 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cern!osilva From: osilva@cern.ch (Olga Silva) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996May15.042243.6327@cern.ch> Date: Wed, 15 May 1996 04:22:43 GMT References: <1996May12.162343.7055@panix.com> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: Netscape 1.1N Lines: 11 In article <1996May12.162343.7055@panix.com>, gsokolov@panix.com (Graham Sokolov) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 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. If you are posting from AOL, please read RFC 1036 before posting again. -- Olga Silva *PLONK* filter active for trolls. Atari Falcon 030 - NetBSD 1.0