From fgarcia@hanse.de Wed Oct 05 21:43:18 1994 Path: ashpoly!cascade!transat!eunet-de!hansebox!hanse!fgarcia From: fgarcia@hanse.de (Freya García) Newsgroups: comp.dsp Subject: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Oct05.214318.6833@hanse.de> Date: Wed, 05 Oct 1994 21:43:18 GMT Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.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 standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Freya García SupraFAXModem 28.8 @ 9600 Telebit bps "When every node is whole, the channel opens." From omoreau@kiae.su Thu Oct 06 08:58:18 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!kiae!omoreau From: omoreau@kiae.su (Olga Moreau) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Oct06.085818.6671@kiae.su> Date: Thu, 06 Oct 1994 08:58:18 GMT References: <1994Oct05.214318.6833@hanse.de> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: WinVN 0.99.5 Lines: 12 In article <1994Oct05.214318.6833@hanse.de>, fgarcia@hanse.de (Freya García) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. If you are posting from AOL, please read RFC 1036 before posting again. -- Olga Moreau *PLONK* filter active for trolls. PC-9821Ap2 (NEC) - NetBSD 1.0 From bito@cam.ac.uk Sat Oct 08 01:59:18 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!cam!bito From: bito@cam.ac.uk (Bill Ito) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Oct08.015918.7270@cam.ac.uk> Date: Sat, 08 Oct 1994 01:59:18 GMT References: <1994Oct05.214318.6833@hanse.de> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: Netscape 1.1N Lines: 8 In article <1994Oct05.214318.6833@hanse.de>, fgarcia@hanse.de (Freya García) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Bill Ito -- University of Cambridge Computer Laboratory "A soul is not exclusive to biology." From rmoreno@uni-hamburg.de Mon Oct 10 05:29:18 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!uni-hamburg!rmoreno From: rmoreno@uni-hamburg.de (Rodrigo Moreno) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Oct10.052918.1976@uni-hamburg.de> Date: Mon, 10 Oct 1994 05:29:18 GMT References: <1994Oct05.214318.6833@hanse.de> <1994Oct08.015918.7270@cam.ac.uk> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1994Oct08.015918.7270@cam.ac.uk>, bito@cam.ac.uk (Bill Ito) 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. -- Rodrigo Moreno | rmoreno@uni-hamburg.de PGP Key fingerprint: 4D77 97B3 3A17 E773 "Keep the channels open." From mweber@purdue.edu Mon Oct 10 12:00:18 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!purdue!mweber From: mweber@purdue.edu (Mikhail Weber) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Oct10.120018.4238@purdue.edu> Date: Mon, 10 Oct 1994 12:00:18 GMT References: <1994Oct05.214318.6833@hanse.de> Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1994Oct05.214318.6833@hanse.de>, fgarcia@hanse.de (Freya García) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > 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. -- Mikhail Weber Tape trading list upon request. SASE required for international mail.