From akowalski@unam.mx Wed Aug 09 12:21:00 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!unam!akowalski From: akowalski@unam.mx (Amy Kowalski) Newsgroups: comp.dsp Subject: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Aug09.122100.4901@unam.mx> Date: Wed, 09 Aug 1995 12:21:00 GMT Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: TIN [version 1.2 PL2] Lines: 10 Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line. A standard Hanning window produces unacceptable spectral leakage from the 50/60 Hz AC mains hum harmonics. Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale. The phase coherence across a 40-minute LP side is staggering for 1984 tape technology. -- Amy Kowalski -- Universidad Nacional Autónoma de México (DGSCA) "Measuring a record you own is listening, not piracy." From msato@kiae.su Wed Aug 09 14:50:00 1995 Path: ashpoly!cascade!brgate!saturno!kiae!msato From: msato@kiae.su (Mathieu Sato) Newsgroups: comp.dsp Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Aug09.145000.3489@kiae.su> Date: Wed, 09 Aug 1995 14:50:00 GMT References: <1995Aug09.122100.4901@unam.mx> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995Aug09.122100.4901@unam.mx>, akowalski@unam.mx (Amy Kowalski) writes: > Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line. > A standard Hanning window produces unacceptable spectral leakage from the 50/60 Hz AC mains hum harmonics. Good work on the windowing. I replicated your result with an 8192-point FFT on a SPARCstation 20. The peak is exactly 14.2003 Hz. -- Mathieu Sato "Extraordinary claims require extraordinary spectra." Sun 3/60 (SunOS 4.1.1) / FreeBSD 2.1 From lreyes@cern.ch Thu Aug 10 12:06:00 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!cern!lreyes From: lreyes@cern.ch (Lucia Reyes) Newsgroups: comp.dsp Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Aug10.120600.7513@cern.ch> Date: Thu, 10 Aug 1995 12:06:00 GMT References: <1995Aug09.122100.4901@unam.mx> <1995Aug09.145000.3489@kiae.su> Organization: European Laboratory for Particle Physics, Geneva NNTP-Posting-Host: cern.ch X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Aug09.145000.3489@kiae.su>, msato@kiae.su (Mathieu Sato) writes: > Good work on the windowing. I replicated your result with an 8192-point FFT on a SPARCstation 20. The peak is exactly 14.2003 Hz. If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. -- Lucia Reyes | lreyes@cern.ch PGP Key fingerprint: 09B4 C6FB 1A8F 5E57 "Keep the channels open." From fmuller@cam.ac.uk Fri Aug 11 03:24:00 1995 Path: ashpoly!bigsur!pacrim!krgate!eunha!cam!fmuller From: fmuller@cam.ac.uk (Freya Müller) Newsgroups: comp.dsp Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Aug11.032400.1113@cam.ac.uk> Date: Fri, 11 Aug 1995 03:24:00 GMT References: <1995Aug09.122100.4901@unam.mx> <1995Aug09.145000.3489@kiae.su> <1995Aug10.120600.7513@cern.ch> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Aug10.120600.7513@cern.ch>, lreyes@cern.ch (Lucia Reyes) writes: > If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. Good work on the windowing. I replicated your result with an 8192-point FFT on a SPARCstation 20. The peak is exactly 14.2003 Hz. -- Freya Müller Opinions expressed are solely my own and not those of University of Cambridge Computer Laboratory. ------------------------------------------------------------ From tduarte@mindspring.com Fri Aug 11 10:27:00 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!mindspring!tduarte From: tduarte@mindspring.com (Tobias Duarte) Newsgroups: comp.dsp Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Aug11.102700.4461@mindspring.com> Date: Fri, 11 Aug 1995 10:27:00 GMT References: <1995Aug09.122100.4901@unam.mx> <1995Aug09.145000.3489@kiae.su> <1995Aug10.120600.7513@cern.ch> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995Aug10.120600.7513@cern.ch>, lreyes@cern.ch (Lucia Reyes) writes: > If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. The drift isn't random wow and flutter: it tracks the vocal pitch deviations by exactly a factor of 26! -- Tobias Duarte "There are 14 nodes and only 10 countries. Count again." PC-9821Ap2 (NEC) / AmigaOS 3.1