From echoi@purdue.edu Sat Mar 18 02:30:56 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!purdue!echoi From: echoi@purdue.edu (Emi Choi) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar18.023056.4026@purdue.edu> Date: Sat, 18 Mar 1995 02:30:56 GMT Organization: Purdue University Engineering Computer Network NNTP-Posting-Host: purdue.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 10 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. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Emi Choi -- Purdue University Engineering Computer Network "5 sigma is a discovery. 7 is a question." From tlindqvist@inria.fr Sat Mar 18 15:04:56 1995 Path: ashpoly!cascade!transat!eunet-de!hansebox!inria!tlindqvist From: tlindqvist@inria.fr (Tomas Lindqvist) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar18.150456.5217@inria.fr> Date: Sat, 18 Mar 1995 15:04:56 GMT References: <1995Mar18.023056.4026@purdue.edu> Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1995Mar18.023056.4026@purdue.edu>, echoi@purdue.edu (Emi Choi) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Tomas Lindqvist | tlindqvist@inria.fr PGP Key fingerprint: 2ED1 8C86 66A4 5EA1 "Keep the channels open." From bsilva@cern.ch Sat Mar 18 17:43:56 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!cern!bsilva From: bsilva@cern.ch (Brian Silva) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar18.174356.8243@cern.ch> Date: Sat, 18 Mar 1995 17:43:56 GMT References: <1995Mar18.023056.4026@purdue.edu> <1995Mar18.150456.5217@inria.fr> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Mar18.150456.5217@inria.fr>, tlindqvist@inria.fr (Tomas Lindqvist) writes: > Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 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. -- Brian Silva | bsilva@cern.ch PGP Key fingerprint: 8979 A236 54D6 1DB5 "Keep the channels open." From stanaka@utexas.edu Sun Mar 19 05:30:56 1995 Path: ashpoly!cascade!brgate!saturno!utexas!stanaka From: stanaka@utexas.edu (Seo-yeon Tanaka) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar19.053056.3523@utexas.edu> Date: Sun, 19 Mar 1995 05:30:56 GMT References: <1995Mar18.023056.4026@purdue.edu> <1995Mar18.150456.5217@inria.fr> <1995Mar18.174356.8243@cern.ch> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Mar18.174356.8243@cern.ch>, bsilva@cern.ch (Brian Silva) 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- === Seo-yeon Tanaka === Dept of Electrical Engineering, University of Texas at Austin "Hold for relay." From msouza@illinois.edu Mon Mar 20 11:08:56 1995 Path: ashpoly!cascade!transat!ukc!fennimore!illinois!msouza From: msouza@illinois.edu (Mei Souza) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1995Mar20.110856.8858@illinois.edu> Date: Mon, 20 Mar 1995 11:08:56 GMT References: <1995Mar18.023056.4026@purdue.edu> <1995Mar18.150456.5217@inria.fr> <1995Mar18.174356.8243@cern.ch> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1995Mar18.174356.8243@cern.ch>, bsilva@cern.ch (Brian Silva) 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. My 14.4k connection dropped twice trying to fetch this thread. Keep articles concise! -- Mei Souza SupraFAXModem 28.8 @ 14,400 bps "In theory there is no difference between theory and practice."