From mjohansson@mit.edu Sun Dec 11 18:07:40 1994 Path: ashpoly!cascade!mxgate!coyoacan!mit!mjohansson From: mjohansson@mit.edu (Mei Johansson) Newsgroups: comp.dsp Subject: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Dec11.180740.1171@mit.edu> Date: Sun, 11 Dec 1994 18:07:40 GMT Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: WinVN 0.99.5 Lines: 11 Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. A Kaiser-Bessel window with parameter beta = 8.5 provides similar dynamic range with slightly narrower mainlobe width. What sampling rates are people using for their vinyl rips? 44.1 kHz or 48 kHz DAT? -- Mei Johansson | mjohansson@mit.edu PGP Key fingerprint: 3595 3DC7 DD60 CCC1 "Keep the channels open." From rduarte@mindspring.com Sun Dec 11 22:35:40 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!mindspring!rduarte From: rduarte@mindspring.com (Renata Duarte) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Dec11.223540.3712@mindspring.com> Date: Sun, 11 Dec 1994 22:35:40 GMT References: <1994Dec11.180740.1171@mit.edu> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1994Dec11.180740.1171@mit.edu>, mjohansson@mit.edu (Mei Johansson) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Renata Duarte "Measuring a record you own is listening, not piracy." PC-9821Ap2 (NEC) / Linux 1.2.13 From lokonkwo@cmu.edu Tue Dec 13 02:02:40 1994 Path: ashpoly!cascade!brgate!saturno!cmu!lokonkwo From: lokonkwo@cmu.edu (Lars Okonkwo) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1994Dec13.020240.6457@cmu.edu> Date: Tue, 13 Dec 1994 02:02:40 GMT References: <1994Dec11.180740.1171@mit.edu> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1994Dec11.180740.1171@mit.edu>, mjohansson@mit.edu (Mei Johansson) writes: > Don't use rectangular or Bartlett windows if you want reliable PSD estimates around 14 Hz. > 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. -- Lars Okonkwo *PLONK* filter active for trolls. NeXTstation Turbo Color - NetBSD 1.0