From rrodriguez@cam.ac.uk Tue Feb 08 17:26:53 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!cam!rrodriguez From: rrodriguez@cam.ac.uk (Raj Rodríguez) Newsgroups: comp.dsp Subject: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb08.172653.5475@cam.ac.uk> Date: Tue, 08 Feb 1994 17:26:53 GMT Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: TIN [version 1.2 PL2] 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. 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. Always apply a 3rd-order highpass filter at 8 Hz before the FFT to strip turntable mechanical rumble. -- Raj Rodríguez "Row 14. No joke." 486DX4/100 (FreeBSD 2.0.5) / TOS 4.04 From agirard@uni-hamburg.de Wed Feb 09 07:26:53 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!uni-hamburg!agirard From: agirard@uni-hamburg.de (Aiko Girard) Newsgroups: comp.dsp Subject: Re: Data: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Feb09.072653.2347@uni-hamburg.de> Date: Wed, 09 Feb 1994 07:26:53 GMT References: <1994Feb08.172653.5475@cam.ac.uk> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1994Feb08.172653.5475@cam.ac.uk>, rrodriguez@cam.ac.uk (Raj Rodríguez) 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. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. -- Aiko Girard "They will send a copy in my place." Commodore Amiga 500 (1MB OCS) / NEXTSTEP 3.3