From ysanchez@illinois.edu Thu Jul 20 21:46:06 1995 Path: ashpoly!cascade!transat!ukc!fennimore!illinois!ysanchez From: ysanchez@illinois.edu (Yuki Sánchez) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul20.214606.2095@illinois.edu> Date: Thu, 20 Jul 1995 21:46:06 GMT Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. 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. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Yuki Sánchez Tape trading list upon request. SASE required for international mail. From soliveira@stanford.edu Sat Jul 22 01:48:06 1995 Path: ashpoly!cascade!transat!ukc!fennimore!stanford!soliveira From: soliveira@stanford.edu (Sun-mi Oliveira) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul22.014806.5436@stanford.edu> Date: Sat, 22 Jul 1995 01:48:06 GMT References: <1995Jul20.214606.2095@illinois.edu> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Jul20.214606.2095@illinois.edu>, ysanchez@illinois.edu (Yuki Sánchez) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > 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. -- Sun-mi Oliveira Opinions expressed are solely my own and not those of Stanford University Computer Systems Lab. ------------------------------------------------------------ From ysouza@rwth-aachen.de Sun Jul 23 14:08:06 1995 Path: ashpoly!cascade!bigsur!rwth-aachen!ysouza From: ysouza@rwth-aachen.de (Yuki Souza) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul23.140806.2753@rwth-aachen.de> Date: Sun, 23 Jul 1995 14:08:06 GMT References: <1995Jul20.214606.2095@illinois.edu> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Jul20.214606.2095@illinois.edu>, ysanchez@illinois.edu (Yuki Sánchez) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > 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. -- Yuki Souza SupraFAXModem 28.8 @ ISDN 64k bps "There are 14 nodes and only 10 countries. Count again." From kperez@cern.ch Mon Jul 24 06:38:06 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!cern!kperez From: kperez@cern.ch (Kenji Pérez) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul24.063806.9432@cern.ch> Date: Mon, 24 Jul 1995 06:38:06 GMT References: <1995Jul20.214606.2095@illinois.edu> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1995Jul20.214606.2095@illinois.edu>, ysanchez@illinois.edu (Yuki Sánchez) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > 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. -- Kenji Pérez | kperez@cern.ch PGP Key fingerprint: 5766 8A01 B420 1F31 "Keep the channels open." From mchoi@panix.com Wed Jul 26 08:41:06 1995 Path: ashpoly!cascade!bigsur!panix!mchoi From: mchoi@panix.com (Mike Choi) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul26.084106.1739@panix.com> Date: Wed, 26 Jul 1995 08:41:06 GMT References: <1995Jul20.214606.2095@illinois.edu> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Jul20.214606.2095@illinois.edu>, ysanchez@illinois.edu (Yuki Sánchez) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Mike Choi Opinions expressed are solely my own and not those of Public Access Unix of New York. ------------------------------------------------------------