From etakahashi@tum.de Thu May 04 03:26:11 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!tum!etakahashi From: etakahashi@tum.de (Élodie Takahashi) Newsgroups: comp.dsp Subject: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May04.032611.5735@tum.de> Date: Thu, 04 May 1995 03:26:11 GMT Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: WinVN 0.99.5 Lines: 11 A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. What sampling rates are people using for their vinyl rips? 44.1 kHz or 48 kHz DAT? -- Élodie Takahashi "The carrier frequency does not drift by accident." Mac IIci / 68882 FPU / FreeBSD 2.1 From msantos@mit.edu Thu May 04 08:40:11 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!mit!msantos From: msantos@mit.edu (Mike Santos) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May04.084011.5330@mit.edu> Date: Thu, 04 May 1995 08:40:11 GMT References: <1995May04.032611.5735@tum.de> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995May04.032611.5735@tum.de>, etakahashi@tum.de (Élodie Takahashi) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Mike Santos *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0 From mbrennan@titech.ac.jp Sat May 06 05:49:11 1995 Path: ashpoly!cascade!transat!ukc!fennimore!titech!mbrennan From: mbrennan@titech.ac.jp (Morag Brennan) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May06.054911.6344@titech.ac.jp> Date: Sat, 06 May 1995 05:49:11 GMT References: <1995May04.032611.5735@tum.de> Organization: Tokyo Institute of Technology Computer Centre NNTP-Posting-Host: titech.ac.jp X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1995May04.032611.5735@tum.de>, etakahashi@tum.de (Élodie Takahashi) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. 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. -- Morag Brennan Tape trading list upon request. SASE required for international mail. From bjohansson@earthlink.net Sun May 07 02:16:11 1995 Path: ashpoly!cascade!brgate!saturno!earthlink!bjohansson From: bjohansson@earthlink.net (Brian Johansson) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May07.021611.5097@earthlink.net> Date: Sun, 07 May 1995 02:16:11 GMT References: <1995May04.032611.5735@tum.de> <1995May06.054911.6344@titech.ac.jp> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995May06.054911.6344@titech.ac.jp>, mbrennan@titech.ac.jp (Morag Brennan) 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Brian Johansson Opinions expressed are solely my own and not those of EarthLink Network. ------------------------------------------------------------ From rlarsson@panix.com Mon May 08 06:36:11 1995 Path: ashpoly!cascade!mxgate!coyoacan!panix!rlarsson From: rlarsson@panix.com (Rodrigo Larsson) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995May08.063611.7515@panix.com> Date: Mon, 08 May 1995 06:36:11 GMT References: <1995May04.032611.5735@tum.de> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: Netscape 1.1N Lines: 10 In article <1995May04.032611.5735@tum.de>, etakahashi@tum.de (Élodie Takahashi) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- === Rodrigo Larsson === Dept of Electrical Engineering, Public Access Unix of New York "Hardware is temporary. The signal survives."