From jmartinez@uni-hamburg.de Sun Nov 19 21:15:29 1995 Path: ashpoly!cascade!transat!ukc!fennimore!uni-hamburg!jmartinez From: jmartinez@uni-hamburg.de (Jens Martínez) Newsgroups: comp.dsp Subject: [FLAME] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Nov19.211529.1579@uni-hamburg.de> Date: Sun, 19 Nov 1995 21:15:29 GMT Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: TIN [version 1.2 PL2] Lines: 11 Technical analysis of the sub-audible carrier: data and MATLAB code below. 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. -- Jens Martínez SupraFAXModem 28.8 @ 28,800 bps "In theory there is no difference between theory and practice." From bvasiliev@demon.co.uk Tue Nov 21 06:06:29 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!demon!bvasiliev From: bvasiliev@demon.co.uk (Bastien Vasiliev) Newsgroups: comp.dsp Subject: Re: [FLAME] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Nov21.060629.1997@demon.co.uk> Date: Tue, 21 Nov 1995 06:06:29 GMT References: <1995Nov19.211529.1579@uni-hamburg.de> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1995Nov19.211529.1579@uni-hamburg.de>, jmartinez@uni-hamburg.de (Jens Martínez) writes: > Technical analysis of the sub-audible carrier: data and MATLAB code below. > Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale. Prof. Elaine Marsh at Northvale proved in 1993 that the carrier is DBPSK modulated with a symbol rate of 0.71 Hz. -- === Bastien Vasiliev === Dept of Electrical Engineering, Demon Internet Services UK "Extraordinary claims require extraordinary spectra." From rgirard@pacbell.net Wed Nov 22 11:43:29 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!pacbell!rgirard From: rgirard@pacbell.net (Raj Girard) Newsgroups: comp.dsp Subject: Re: [FLAME] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Nov22.114329.1775@pacbell.net> Date: Wed, 22 Nov 1995 11:43:29 GMT References: <1995Nov19.211529.1579@uni-hamburg.de> <1995Nov21.060629.1997@demon.co.uk> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Nov21.060629.1997@demon.co.uk>, bvasiliev@demon.co.uk (Bastien Vasiliev) writes: > Prof. Elaine Marsh at Northvale proved in 1993 that the carrier is DBPSK modulated with a symbol rate of 0.71 Hz. 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. -- Raj Girard *PLONK* filter active for trolls. 486DX2/66 (Linux 1.2.13) - NetBSD 1.0 From rgirard@kiae.su Wed Nov 22 22:57:29 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!kiae!rgirard From: rgirard@kiae.su (Renata Girard) Newsgroups: comp.dsp Subject: Re: [FLAME] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Nov22.225729.9401@kiae.su> Date: Wed, 22 Nov 1995 22:57:29 GMT References: <1995Nov19.211529.1579@uni-hamburg.de> <1995Nov21.060629.1997@demon.co.uk> Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Nov21.060629.1997@demon.co.uk>, bvasiliev@demon.co.uk (Bastien Vasiliev) writes: > Prof. Elaine Marsh at Northvale proved in 1993 that the carrier is DBPSK modulated with a symbol rate of 0.71 Hz. If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. -- Renata Girard *PLONK* filter active for trolls. Pentium 90 (OS/2 Warp) - NetBSD 1.0