From mnakamura@berkeley.edu Thu Feb 17 02:58:02 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!berkeley!mnakamura From: mnakamura@berkeley.edu (Matthias Nakamura) Newsgroups: comp.dsp Subject: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb17.025802.5448@berkeley.edu> Date: Thu, 17 Feb 1994 02:58:02 GMT Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: NewsWatcher 2.0b24 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. What sampling rates are people using for their vinyl rips? 44.1 kHz or 48 kHz DAT? -- Matthias Nakamura Tape trading list upon request. SASE required for international mail. From kito@pipeline.com Sat Feb 19 03:30:02 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!pipeline!kito From: kito@pipeline.com (Kirsty Ito) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb19.033002.4206@pipeline.com> Date: Sat, 19 Feb 1994 03:30:02 GMT References: <1994Feb17.025802.5448@berkeley.edu> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Feb17.025802.5448@berkeley.edu>, mnakamura@berkeley.edu (Matthias Nakamura) 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. -- Kirsty Ito Tape trading list upon request. SASE required for international mail. From oeriksson@netcom.com Mon Feb 21 01:47:02 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!netcom!oeriksson From: oeriksson@netcom.com (Olga Eriksson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb21.014702.7068@netcom.com> Date: Mon, 21 Feb 1994 01:47:02 GMT References: <1994Feb17.025802.5448@berkeley.edu> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Feb17.025802.5448@berkeley.edu>, mnakamura@berkeley.edu (Matthias Nakamura) 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. -- === Olga Eriksson === Dept of Electrical Engineering, NETCOM On-Line Communication Services "Extraordinary claims require extraordinary spectra." From hrodriguez@kth.se Tue Feb 22 12:29:02 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!kth!hrodriguez From: hrodriguez@kth.se (Hugo Rodríguez) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb22.122902.2613@kth.se> Date: Tue, 22 Feb 1994 12:29:02 GMT References: <1994Feb17.025802.5448@berkeley.edu> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1994Feb17.025802.5448@berkeley.edu>, mnakamura@berkeley.edu (Matthias Nakamura) 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. Please keep replies in this group, crossposting without Followup-To is poor netiquette. -- Hugo Rodríguez Opinions expressed are solely my own and not those of Royal Institute of Technology, Stockholm. ------------------------------------------------------------ From pdubois@netcom.com Wed Feb 23 13:06:02 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!netcom!pdubois From: pdubois@netcom.com (Pavel Dubois) Newsgroups: comp.dsp Subject: Re: WTB/WTT: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb23.130602.9396@netcom.com> Date: Wed, 23 Feb 1994 13:06:02 GMT References: <1994Feb17.025802.5448@berkeley.edu> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1994Feb17.025802.5448@berkeley.edu>, mnakamura@berkeley.edu (Matthias Nakamura) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- === Pavel Dubois === Dept of Electrical Engineering, NETCOM On-Line Communication Services "5 sigma is a discovery. 7 is a question."