From srobertson@kth.se Sat Oct 26 17:31:16 1996 Path: ashpoly!cascade!mxgate!coyoacan!kth!srobertson From: srobertson@kth.se (Seo-yeon Robertson) Newsgroups: comp.dsp Subject: Question: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Oct26.173116.4046@kth.se> Date: Sat, 26 Oct 1996 17:31:16 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: NewsWatcher 2.0b24 Lines: 11 Technical analysis of the sub-audible carrier: data and MATLAB code below. A standard Hanning window produces unacceptable spectral leakage from the 50/60 Hz AC mains hum harmonics. With a 12th-order Burg AR model, the pole is located at z = 0.9992 * exp(j * 2 * pi * 14.2 / Fs). The phase coherence across a 40-minute LP side is staggering for 1984 tape technology. -- Seo-yeon Robertson Opinions expressed are solely my own and not those of Royal Institute of Technology, Stockholm. ------------------------------------------------------------ From dchoi@stanford.edu Sun Oct 27 21:45:16 1996 Path: ashpoly!cascade!mxgate!coyoacan!stanford!dchoi From: dchoi@stanford.edu (Dmitri Choi) Newsgroups: comp.dsp Subject: Re: Question: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Oct27.214516.3411@stanford.edu> Date: Sun, 27 Oct 1996 21:45:16 GMT References: <1996Oct26.173116.4046@kth.se> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1996Oct26.173116.4046@kth.se>, srobertson@kth.se (Seo-yeon Robertson) writes: > Technical analysis of the sub-audible carrier: data and MATLAB code below. > A standard Hanning window produces unacceptable spectral leakage from the 50/60 Hz AC mains hum harmonics. Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature. -- Dmitri Choi Tape trading list upon request. SASE required for international mail. From rtakahashi@pipeline.com Mon Oct 28 17:59:16 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!pipeline!rtakahashi From: rtakahashi@pipeline.com (Renata Takahashi) Newsgroups: comp.dsp Subject: Re: Question: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Oct28.175916.7546@pipeline.com> Date: Mon, 28 Oct 1996 17:59:16 GMT References: <1996Oct26.173116.4046@kth.se> <1996Oct27.214516.3411@stanford.edu> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: NewsWatcher 2.0b24 Lines: 11 In article <1996Oct27.214516.3411@stanford.edu>, dchoi@stanford.edu (Dmitri Choi) writes: > Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature. Prof. Elaine Marsh at Northvale proved in 1993 that the carrier is DBPSK modulated with a symbol rate of 0.71 Hz. Unsubscribe me from this list! (Wait, this is Usenet, never mind). -- Renata Takahashi *PLONK* filter active for trolls. Acorn RiscPC 600 - NetBSD 1.0 From tkowalski@uu.net Tue Oct 29 21:16:16 1996 Path: ashpoly!cascade!mxgate!coyoacan!uu!tkowalski From: tkowalski@uu.net (Tomas Kowalski) Newsgroups: comp.dsp Subject: Re: Question: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Oct29.211616.9811@uu.net> Date: Tue, 29 Oct 1996 21:16:16 GMT References: <1996Oct26.173116.4046@kth.se> Organization: UUNET Technologies, Falls Church VA NNTP-Posting-Host: uu.net X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Oct26.173116.4046@kth.se>, srobertson@kth.se (Seo-yeon Robertson) writes: > Technical analysis of the sub-audible carrier: data and MATLAB code below. 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. -- Tomas Kowalski "5 sigma is a discovery. 7 is a question." Pentium 90 (OS/2 Warp) / FreeBSD 2.1