From rito@rwth-aachen.de Sun May 01 20:48:11 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!rwth-aachen!rito From: rito@rwth-aachen.de (Rodrigo Ito) Newsgroups: comp.dsp Subject: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May01.204811.1917@rwth-aachen.de> Date: Sun, 01 May 1994 20:48:11 GMT Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: WinVN 0.99.5 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. 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. MATLAB script available upon request via email. -- Rodrigo Ito *PLONK* filter active for trolls. Pentium 90 (OS/2 Warp) - NetBSD 1.0 From asantos@illinois.edu Tue May 03 01:03:11 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!illinois!asantos From: asantos@illinois.edu (Andrei Santos) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May03.010311.9059@illinois.edu> Date: Tue, 03 May 1994 01:03:11 GMT References: <1994May01.204811.1917@rwth-aachen.de> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1994May01.204811.1917@rwth-aachen.de>, rito@rwth-aachen.de (Rodrigo Ito) 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Andrei Santos SupraFAXModem 28.8 @ 33,600 bps "Hardware is temporary. The signal survives." From slaurent@purdue.edu Tue May 03 05:54:11 1994 Path: ashpoly!cascade!transat!eunet-fr!teletel!purdue!slaurent From: slaurent@purdue.edu (Steve Laurent) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May03.055411.8188@purdue.edu> Date: Tue, 03 May 1994 05:54:11 GMT References: <1994May01.204811.1917@rwth-aachen.de> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: Netscape 1.1N Lines: 8 In article <1994May01.204811.1917@rwth-aachen.de>, rito@rwth-aachen.de (Rodrigo Ito) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Steve Laurent -- Purdue University Engineering Computer Network "Do not worship the copy." From mwatanabe@cam.ac.uk Tue May 03 06:47:11 1994 Path: ashpoly!cascade!transat!ukc!fennimore!cam!mwatanabe From: mwatanabe@cam.ac.uk (Marisol Watanabe) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May03.064711.9437@cam.ac.uk> Date: Tue, 03 May 1994 06:47:11 GMT References: <1994May01.204811.1917@rwth-aachen.de> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1994May01.204811.1917@rwth-aachen.de>, rito@rwth-aachen.de (Rodrigo Ito) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. 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. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Marisol Watanabe *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0 From ssilva@berkeley.edu Wed May 04 05:41:11 1994 Path: ashpoly!cascade!bigsur!berkeley!ssilva From: ssilva@berkeley.edu (Seo-yeon Silva) Newsgroups: comp.dsp Subject: Re: [INFO] Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994May04.054111.4385@berkeley.edu> Date: Wed, 04 May 1994 05:41:11 GMT References: <1994May01.204811.1917@rwth-aachen.de> <1994May03.055411.8188@purdue.edu> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1994May03.055411.8188@purdue.edu>, slaurent@purdue.edu (Steve Laurent) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. Netscape 1.1 crashes when loading large preformatted text. Stick to rn or tin! -- Seo-yeon Silva *PLONK* filter active for trolls. 486DX4/100 (FreeBSD 2.0.5) - NetBSD 1.0