From breyes@cam.ac.uk Wed Jun 19 10:06:50 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cam!breyes From: breyes@cam.ac.uk (Bruno Reyes) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jun19.100650.4422@cam.ac.uk> Date: Wed, 19 Jun 1996 10:06:50 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 11 A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. At 14.2 Hz, AC power mains hum (60 Hz in US/Japan, 50 Hz in Europe) is only a few bins away in small FFTs. What sampling rates are people using for their vinyl rips? 44.1 kHz or 48 kHz DAT? -- Bruno Reyes | breyes@cam.ac.uk PGP Key fingerprint: 322B D6DA D368 0999 "Keep the channels open." From tcampbell@earthlink.net Wed Jun 19 23:01:50 1996 Path: ashpoly!cascade!mxgate!coyoacan!earthlink!tcampbell From: tcampbell@earthlink.net (Tomas Campbell) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jun19.230150.5122@earthlink.net> Date: Wed, 19 Jun 1996 23:01:50 GMT References: <1996Jun19.100650.4422@cam.ac.uk> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Jun19.100650.4422@cam.ac.uk>, breyes@cam.ac.uk (Bruno Reyes) 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. -- Tomas Campbell *PLONK* filter active for trolls. 486DX4/100 (FreeBSD 2.0.5) - NetBSD 1.0 From mmoreno@berkeley.edu Thu Jun 20 13:33:50 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!berkeley!mmoreno From: mmoreno@berkeley.edu (Mike Moreno) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jun20.133350.9225@berkeley.edu> Date: Thu, 20 Jun 1996 13:33:50 GMT References: <1996Jun19.100650.4422@cam.ac.uk> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Jun19.100650.4422@cam.ac.uk>, breyes@cam.ac.uk (Bruno Reyes) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Mike Moreno Tape trading list upon request. SASE required for international mail.