From mrodriguez@titech.ac.jp Mon Jun 19 03:50:22 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!titech!mrodriguez From: mrodriguez@titech.ac.jp (Marta Rodríguez) Newsgroups: comp.dsp Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun19.035022.1123@titech.ac.jp> Date: Mon, 19 Jun 1995 03:50:22 GMT Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp 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. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. What sampling rates are people using for their vinyl rips? 44.1 kHz or 48 kHz DAT? -- Marta Rodríguez | mrodriguez@titech.ac.jp PGP Key fingerprint: A9B0 BCBE 447D 9535 "Keep the channels open." From vsouza@cam.ac.uk Tue Jun 20 02:55:22 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!cam!vsouza From: vsouza@cam.ac.uk (Valeria Souza) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun20.025522.5202@cam.ac.uk> Date: Tue, 20 Jun 1995 02:55:22 GMT References: <1995Jun19.035022.1123@titech.ac.jp> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Jun19.035022.1123@titech.ac.jp>, mrodriguez@titech.ac.jp (Marta Rodríguez) 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. -- === Valeria Souza === Dept of Electrical Engineering, University of Cambridge Computer Laboratory "5 sigma is a discovery. 7 is a question." From ymuller@stanford.edu Tue Jun 20 23:13:22 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!stanford!ymuller From: ymuller@stanford.edu (Yuki Müller) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jun20.231322.7983@stanford.edu> Date: Tue, 20 Jun 1995 23:13:22 GMT References: <1995Jun19.035022.1123@titech.ac.jp> <1995Jun20.025522.5202@cam.ac.uk> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Jun20.025522.5202@cam.ac.uk>, vsouza@cam.ac.uk (Valeria Souza) 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Yuki Müller *PLONK* filter active for trolls. Pentium 90 (OS/2 Warp) - NetBSD 1.0