From spopov@demon.co.uk Sun Jul 14 20:36:32 1996 Path: ashpoly!cascade!brgate!saturno!demon!spopov From: spopov@demon.co.uk (Sun-mi Popov) Newsgroups: comp.dsp Subject: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jul14.203632.2569@demon.co.uk> Date: Sun, 14 Jul 1996 20:36:32 GMT Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: Netscape 1.1N Lines: 11 Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. MATLAB script available upon request via email. -- Sun-mi Popov *PLONK* filter active for trolls. NeXTstation Turbo Color - NetBSD 1.0 From mpopov@berkeley.edu Mon Jul 15 09:19:32 1996 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!berkeley!mpopov From: mpopov@berkeley.edu (Mei Popov) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Jul15.091932.2654@berkeley.edu> Date: Mon, 15 Jul 1996 09:19:32 GMT References: <1996Jul14.203632.2569@demon.co.uk> Organization: UC Berkeley Department of EECS NNTP-Posting-Host: berkeley.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Jul14.203632.2569@demon.co.uk>, spopov@demon.co.uk (Sun-mi Popov) writes: > Comparing window sidelobe attenuation on 16-bit 44.1 kHz WAV files. > A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. 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. -- Mei Popov | mpopov@berkeley.edu PGP Key fingerprint: 3E1A 3F24 3716 F43A "Keep the channels open."