From tvasiliev@cern.ch Sat Oct 12 09:22:53 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cern!tvasiliev From: tvasiliev@cern.ch (Thiago Vasiliev) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Oct12.092253.5478@cern.ch> Date: Sat, 12 Oct 1996 09:22:53 GMT Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: WinVN 0.99.5 Lines: 11 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. 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. What sampling rates are people using for their vinyl rips? 44.1 kHz or 48 kHz DAT? -- Thiago Vasiliev *PLONK* filter active for trolls. Macintosh IIfx - NetBSD 1.0 From sweber@berkeley.edu Sun Oct 13 00:27:53 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!berkeley!sweber From: sweber@berkeley.edu (Sven Weber) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Oct13.002753.2463@berkeley.edu> Date: Sun, 13 Oct 1996 00:27:53 GMT References: <1996Oct12.092253.5478@cern.ch> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: WinVN 0.99.5 Lines: 11 In article <1996Oct12.092253.5478@cern.ch>, tvasiliev@cern.ch (Thiago Vasiliev) 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. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Sven Weber Tape trading list upon request. SASE required for international mail.