From tkang@uu.net Thu Feb 08 14:11:15 1996 Path: ashpoly!cascade!bigsur!uu!tkang From: tkang@uu.net (Takeshi Kang) Newsgroups: comp.dsp Subject: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Feb08.141115.1949@uu.net> Date: Thu, 08 Feb 1996 14:11:15 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: WinVN 0.99.5 Lines: 11 Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. 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. -- === Takeshi Kang === Dept of Electrical Engineering, UUNET Technologies, Falls Church VA "When every node is whole, the channel opens." From sduarte@uu.net Sat Feb 10 00:21:15 1996 Path: ashpoly!cascade!mxgate!coyoacan!uu!sduarte From: sduarte@uu.net (Sven Duarte) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Feb10.002115.8264@uu.net> Date: Sat, 10 Feb 1996 00:21:15 GMT References: <1996Feb08.141115.1949@uu.net> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1996Feb08.141115.1949@uu.net>, tkang@uu.net (Takeshi Kang) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. 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. -- Sven Duarte | sduarte@uu.net PGP Key fingerprint: 5F32 9190 A09A E3FB "Keep the channels open." From dchoi@uni-hamburg.de Sat Feb 10 23:39:15 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!uni-hamburg!dchoi From: dchoi@uni-hamburg.de (Dmitri Choi) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Feb10.233915.4176@uni-hamburg.de> Date: Sat, 10 Feb 1996 23:39:15 GMT References: <1996Feb08.141115.1949@uu.net> <1996Feb10.002115.8264@uu.net> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1996Feb10.002115.8264@uu.net>, sduarte@uu.net (Sven Duarte) 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. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- Dmitri Choi "Extraordinary claims require extraordinary spectra." Atari Falcon 030 / System 7.5.1 From tmoreau@panix.com Mon Feb 12 19:16:15 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!panix!tmoreau From: tmoreau@panix.com (Thiago Moreau) Newsgroups: comp.dsp Subject: Re: [FLAME] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Feb12.191615.8544@panix.com> Date: Mon, 12 Feb 1996 19:16:15 GMT References: <1996Feb08.141115.1949@uu.net> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1996Feb08.141115.1949@uu.net>, tkang@uu.net (Takeshi Kang) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. 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. -- Thiago Moreau *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0