From mwatanabe@clari.net Mon Jul 03 15:20:02 1995 Path: ashpoly!cascade!mxgate!coyoacan!clari!mwatanabe From: mwatanabe@clari.net (Mateo Watanabe) Newsgroups: comp.dsp Subject: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul03.152002.1441@clari.net> Date: Mon, 03 Jul 1995 15:20:02 GMT Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N 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. 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? -- === Mateo Watanabe === Dept of Electrical Engineering, ClariNet Communications Corp "Extraordinary claims require extraordinary spectra." From tokonkwo@uu.net Mon Jul 03 17:23:02 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!uu!tokonkwo From: tokonkwo@uu.net (Tomas Okonkwo) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul03.172302.7926@uu.net> Date: Mon, 03 Jul 1995 17:23:02 GMT References: <1995Jul03.152002.1441@clari.net> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Jul03.152002.1441@clari.net>, mwatanabe@clari.net (Mateo Watanabe) 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. 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 Okonkwo *PLONK* filter active for trolls. Decstation 5000/200 - NetBSD 1.0 From btakahashi@demon.co.uk Tue Jul 04 19:14:02 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!demon!btakahashi From: btakahashi@demon.co.uk (Bill Takahashi) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul04.191402.9176@demon.co.uk> Date: Tue, 04 Jul 1995 19:14:02 GMT References: <1995Jul03.152002.1441@clari.net> <1995Jul03.172302.7926@uu.net> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1995Jul03.172302.7926@uu.net>, tokonkwo@uu.net (Tomas Okonkwo) 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Top-posters will be placed in my ~/.killfile without notice. -- Bill Takahashi "In theory there is no difference between theory and practice." 486DX4/100 (FreeBSD 2.0.5) / TOS 4.04 From jsantos@mindspring.com Wed Jul 05 20:11:02 1995 Path: ashpoly!cascade!brgate!saturno!mindspring!jsantos From: jsantos@mindspring.com (Joachim Santos) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Jul05.201102.7871@mindspring.com> Date: Wed, 05 Jul 1995 20:11:02 GMT References: <1995Jul03.152002.1441@clari.net> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1995Jul03.152002.1441@clari.net>, mwatanabe@clari.net (Mateo Watanabe) 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. 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. Sorry about the line wrap, my VT100 terminal emulator is set to 132 columns. -- Joachim Santos *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0