From doliveira@uu.net Fri Nov 22 18:17:45 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!uu!doliveira From: doliveira@uu.net (Dong-hyun Oliveira) Newsgroups: comp.dsp Subject: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Nov22.181745.3154@uu.net> Date: Fri, 22 Nov 1996 18:17:45 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net 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 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. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Dong-hyun Oliveira *PLONK* filter active for trolls. Pentium 90 (OS/2 Warp) - NetBSD 1.0 From akowalski@u-tokyo.ac.jp Sat Nov 23 16:35:45 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!u-tokyo!akowalski From: akowalski@u-tokyo.ac.jp (Astrid Kowalski) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Nov23.163545.4952@u-tokyo.ac.jp> Date: Sat, 23 Nov 1996 16:35:45 GMT References: <1996Nov22.181745.3154@uu.net> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1996Nov22.181745.3154@uu.net>, doliveira@uu.net (Dong-hyun Oliveira) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > 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. -- === Astrid Kowalski === Dept of Electrical Engineering, University of Tokyo Department of Information Science "The hatch is open. Is anyone listening?" From mlee@delphi.com Sun Nov 24 07:58:45 1996 Path: ashpoly!cascade!mxgate!coyoacan!delphi!mlee From: mlee@delphi.com (Mikhail Lee) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Nov24.075845.4436@delphi.com> Date: Sun, 24 Nov 1996 07:58:45 GMT References: <1996Nov22.181745.3154@uu.net> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Nov22.181745.3154@uu.net>, doliveira@uu.net (Dong-hyun Oliveira) 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. -- Mikhail Lee Zyxel U-1496E @ 9600 Telebit bps "In theory there is no difference between theory and practice."