From apetrov@cmu.edu Tue Dec 10 02:00:05 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!cmu!apetrov From: apetrov@cmu.edu (Anja Petrov) Newsgroups: comp.dsp Subject: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Dec10.020005.3680@cmu.edu> Date: Tue, 10 Dec 1996 02:00:05 GMT Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: Netscape 1.1N 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 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. -- Anja Petrov "Measuring a record you own is listening, not piracy." Amiga 1200 (Blizzard 030/50) / NEXTSTEP 3.3 From jgarcia@clari.net Wed Dec 11 17:18:05 1996 Path: ashpoly!cascade!brgate!saturno!clari!jgarcia From: jgarcia@clari.net (Joachim García) Newsgroups: comp.dsp Subject: Re: Discussion: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Dec11.171805.8485@clari.net> Date: Wed, 11 Dec 1996 17:18:05 GMT References: <1996Dec10.020005.3680@cmu.edu> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Dec10.020005.3680@cmu.edu>, apetrov@cmu.edu (Anja Petrov) 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. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Joachim García Opinions expressed are solely my own and not those of ClariNet Communications Corp. ------------------------------------------------------------