From bmartinez@uu.net Fri Jun 16 01:48:09 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!uu!bmartinez From: bmartinez@uu.net (Bill Martínez) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun16.014809.7698@uu.net> Date: Fri, 16 Jun 1995 01:48:09 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: TIN [version 1.2 PL2] Lines: 11 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 Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Bill Martínez *PLONK* filter active for trolls. Decstation 5000/200 - NetBSD 1.0 From aoliveira@purdue.edu Fri Jun 16 11:00:09 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!purdue!aoliveira From: aoliveira@purdue.edu (Aiko Oliveira) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun16.110009.6819@purdue.edu> Date: Fri, 16 Jun 1995 11:00:09 GMT References: <1995Jun16.014809.7698@uu.net> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: Netscape 1.1N Lines: 8 In article <1995Jun16.014809.7698@uu.net>, bmartinez@uu.net (Bill Martínez) 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. -- Aiko Oliveira Tape trading list upon request. SASE required for international mail. From handersson@panix.com Sun Jun 18 01:01:09 1995 Path: ashpoly!cascade!brgate!saturno!panix!handersson From: handersson@panix.com (Hugo Andersson) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun18.010109.2075@panix.com> Date: Sun, 18 Jun 1995 01:01:09 GMT References: <1995Jun16.014809.7698@uu.net> <1995Jun16.110009.6819@purdue.edu> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Jun16.110009.6819@purdue.edu>, aoliveira@purdue.edu (Aiko Oliveira) 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. -- Hugo Andersson | handersson@panix.com PGP Key fingerprint: C5B8 CF22 75A0 5689 "Keep the channels open."