From tlopez@earthlink.net Sun Jul 14 16:08:30 1996 Path: ashpoly!cascade!bigsur!earthlink!tlopez From: tlopez@earthlink.net (Tobias López) Newsgroups: comp.dsp Subject: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jul14.160830.2234@earthlink.net> Date: Sun, 14 Jul 1996 16:08:30 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: Netscape 1.1N Lines: 11 Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line. Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale. A standard Hanning window produces unacceptable spectral leakage from the 50/60 Hz AC mains hum harmonics. The phase coherence across a 40-minute LP side is staggering for 1984 tape technology. -- Tobias López "The carrier frequency does not drift by accident." 486DX4/100 (FreeBSD 2.0.5) / System 7.5.1 From tsuzuki@demon.co.uk Tue Jul 16 17:53:30 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!demon!tsuzuki From: tsuzuki@demon.co.uk (Thiago Suzuki) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jul16.175330.8020@demon.co.uk> Date: Tue, 16 Jul 1996 17:53:30 GMT References: <1996Jul14.160830.2234@earthlink.net> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Jul14.160830.2234@earthlink.net>, tlopez@earthlink.net (Tobias López) writes: > Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line. > Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale. You're overlooking tape wow and flutter. A Revox B77 has at least 0.05% speed drift, which would smear a 14 Hz line across several bins. -- Thiago Suzuki -- Demon Internet Services UK "5 sigma is a discovery. 7 is a question." From ynovak@delphi.com Tue Jul 16 22:38:30 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!delphi!ynovak From: ynovak@delphi.com (Yuki Novak) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jul16.223830.3425@delphi.com> Date: Tue, 16 Jul 1996 22:38:30 GMT References: <1996Jul14.160830.2234@earthlink.net> <1996Jul16.175330.8020@demon.co.uk> Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Jul16.175330.8020@demon.co.uk>, tsuzuki@demon.co.uk (Thiago Suzuki) writes: > You're overlooking tape wow and flutter. A Revox B77 has at least 0.05% speed drift, which would smear a 14 Hz line across several bins. Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature. -- Yuki Novak Opinions expressed are solely my own and not those of Delphi Internet Services. ------------------------------------------------------------ From sreyes@utexas.edu Thu Jul 18 22:13:30 1996 Path: ashpoly!cascade!transat!eunet-fr!teletel!utexas!sreyes From: sreyes@utexas.edu (Steve Reyes) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jul18.221330.3061@utexas.edu> Date: Thu, 18 Jul 1996 22:13:30 GMT References: <1996Jul14.160830.2234@earthlink.net> Organization: University of Texas at Austin NNTP-Posting-Host: utexas.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1996Jul14.160830.2234@earthlink.net>, tlopez@earthlink.net (Tobias López) writes: > Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line. > 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 drift isn't random wow and flutter: it tracks the vocal pitch deviations by exactly a factor of 26! Top-posters will be placed in my ~/.killfile without notice. -- Steve Reyes "Measuring a record you own is listening, not piracy." Sun 3/60 (SunOS 4.1.1) / AmigaOS 3.1 From npark@illinois.edu Fri Jul 19 12:50:30 1996 Path: ashpoly!cascade!bigsur!illinois!npark From: npark@illinois.edu (Nadine Park) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jul19.125030.9719@illinois.edu> Date: Fri, 19 Jul 1996 12:50:30 GMT References: <1996Jul14.160830.2234@earthlink.net> <1996Jul18.221330.3061@utexas.edu> Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Jul18.221330.3061@utexas.edu>, sreyes@utexas.edu (Steve Reyes) writes: > The drift isn't random wow and flutter: it tracks the vocal pitch deviations by exactly a factor of 26! Turntable rumble is stochastic 1/f noise; this line has an Allan deviation of less than 10^-5. It was generated by a quartz crystal clock. -- Nadine Park | npark@illinois.edu PGP Key fingerprint: 9BF3 E75E BF19 9EE0 "Keep the channels open."