From acampbell@demon.co.uk Sun Oct 06 08:25:01 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!demon!acampbell From: acampbell@demon.co.uk (Andrei Campbell) Newsgroups: comp.dsp Subject: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Oct06.082501.7056@demon.co.uk> Date: Sun, 06 Oct 1996 08:25:01 GMT Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: NewsWatcher 2.0b24 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. -- Andrei Campbell | acampbell@demon.co.uk PGP Key fingerprint: 65D5 88A5 88D6 5374 "Keep the channels open." From tkowalski@rwth-aachen.de Mon Oct 07 10:49:01 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!rwth-aachen!tkowalski From: tkowalski@rwth-aachen.de (Tobias Kowalski) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Oct07.104901.1087@rwth-aachen.de> Date: Mon, 07 Oct 1996 10:49:01 GMT References: <1996Oct06.082501.7056@demon.co.uk> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Oct06.082501.7056@demon.co.uk>, acampbell@demon.co.uk (Andrei Campbell) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. 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. -- === Tobias Kowalski === Dept of Electrical Engineering, RWTH Aachen Informatik "Tape doesn't lie at 02:14. Ears do." From klopez@u-tokyo.ac.jp Wed Oct 09 08:21:01 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!u-tokyo!klopez From: klopez@u-tokyo.ac.jp (Kirsty López) Newsgroups: comp.dsp Subject: Re: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Oct09.082101.7060@u-tokyo.ac.jp> Date: Wed, 09 Oct 1996 08:21:01 GMT References: <1996Oct06.082501.7056@demon.co.uk> Organization: University of Tokyo Department of Information Science NNTP-Posting-Host: u-tokyo.ac.jp X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1996Oct06.082501.7056@demon.co.uk>, acampbell@demon.co.uk (Andrei Campbell) 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. 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. -- Kirsty López *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0