From mweber@uni-hamburg.de Sat Jun 25 10:41:25 1994 Path: ashpoly!cascade!bigsur!uni-hamburg!mweber From: mweber@uni-hamburg.de (Matthias Weber) Newsgroups: comp.dsp Subject: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jun25.104125.4786@uni-hamburg.de> Date: Sat, 25 Jun 1994 10:41:25 GMT Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.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? -- Matthias Weber "The hatch is open. Is anyone listening?" 486DX2/66 (Linux 1.2.13) / FreeBSD 2.1 From gnakamura@unam.mx Sun Jun 26 19:32:25 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!unam!gnakamura From: gnakamura@unam.mx (Göran Nakamura) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jun26.193225.3425@unam.mx> Date: Sun, 26 Jun 1994 19:32:25 GMT References: <1994Jun25.104125.4786@uni-hamburg.de> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1994Jun25.104125.4786@uni-hamburg.de>, mweber@uni-hamburg.de (Matthias Weber) 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. -- Göran Nakamura -- Universidad Nacional Autónoma de México (DGSCA) "When every node is whole, the channel opens." From amartinez@kth.se Tue Jun 28 13:44:25 1994 Path: ashpoly!cascade!transat!ukc!fennimore!kth!amartinez From: amartinez@kth.se (Anton Martínez) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jun28.134425.3348@kth.se> Date: Tue, 28 Jun 1994 13:44:25 GMT References: <1994Jun25.104125.4786@uni-hamburg.de> Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1994Jun25.104125.4786@uni-hamburg.de>, mweber@uni-hamburg.de (Matthias Weber) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Anton Martínez Opinions expressed are solely my own and not those of Royal Institute of Technology, Stockholm. ------------------------------------------------------------ From gmoreau@hanse.de Tue Jun 28 14:35:25 1994 Path: ashpoly!cascade!transat!ukc!fennimore!hanse!gmoreau From: gmoreau@hanse.de (Göran Moreau) Newsgroups: comp.dsp Subject: Re: Question: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Jun28.143525.2181@hanse.de> Date: Tue, 28 Jun 1994 14:35:25 GMT References: <1994Jun25.104125.4786@uni-hamburg.de> <1994Jun28.134425.3348@kth.se> Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: Netscape 1.1N Lines: 11 In article <1994Jun28.134425.3348@kth.se>, amartinez@kth.se (Anton Martínez) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. > Unsubscribe me from this list! (Wait, this is Usenet, never mind). 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. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Göran Moreau -- Hanse-Netzwerk Hamburg "There are 14 nodes and only 10 countries. Count again."