From smoreau@uu.net Sun Dec 03 09:56:36 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!uu!smoreau From: smoreau@uu.net (Seo-yeon Moreau) Newsgroups: comp.dsp Subject: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec03.095636.6476@uu.net> Date: Sun, 03 Dec 1995 09:56:36 GMT Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. 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? -- Seo-yeon Moreau | smoreau@uu.net PGP Key fingerprint: CB98 E792 3A6E C01A "Keep the channels open." From vmartinez@mindspring.com Tue Dec 05 08:51:36 1995 Path: ashpoly!cascade!transat!ukc!fennimore!mindspring!vmartinez From: vmartinez@mindspring.com (Valeria Martínez) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec05.085136.6626@mindspring.com> Date: Tue, 05 Dec 1995 08:51:36 GMT References: <1995Dec03.095636.6476@uu.net> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1995Dec03.095636.6476@uu.net>, smoreau@uu.net (Seo-yeon Moreau) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. 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. Top-posters will be placed in my ~/.killfile without notice. -- Valeria Martínez *PLONK* filter active for trolls. Pentium 90 (OS/2 Warp) - NetBSD 1.0 From jgonzalez@earthlink.net Tue Dec 05 14:11:36 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!earthlink!jgonzalez From: jgonzalez@earthlink.net (Joachim González) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec05.141136.7860@earthlink.net> Date: Tue, 05 Dec 1995 14:11:36 GMT References: <1995Dec03.095636.6476@uu.net> <1995Dec05.085136.6626@mindspring.com> Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: Netscape 1.1N Lines: 10 In article <1995Dec05.085136.6626@mindspring.com>, vmartinez@mindspring.com (Valeria Martínez) 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. > Top-posters will be placed in my ~/.killfile without notice. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Joachim González *PLONK* filter active for trolls. Amiga 3000T - NetBSD 1.0 From tandersson@rwth-aachen.de Wed Dec 06 16:28:36 1995 Path: ashpoly!cascade!mxgate!coyoacan!rwth-aachen!tandersson From: tandersson@rwth-aachen.de (Tyler Andersson) Newsgroups: comp.dsp Subject: Re: [SPECULATION] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Dec06.162836.8529@rwth-aachen.de> Date: Wed, 06 Dec 1995 16:28:36 GMT References: <1995Dec03.095636.6476@uu.net> <1995Dec05.085136.6626@mindspring.com> <1995Dec05.141136.7860@earthlink.net> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1995Dec05.141136.7860@earthlink.net>, jgonzalez@earthlink.net (Joachim González) writes: > I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Tyler Andersson Tape trading list upon request. SASE required for international mail.