From mgonzalez@clari.net Sat Jun 22 06:52:08 1996 Path: ashpoly!bigsur!pacrim!jpgate!kamome!clari!mgonzalez From: mgonzalez@clari.net (Mikhail González) Newsgroups: comp.dsp Subject: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jun22.065208.4274@clari.net> Date: Sat, 22 Jun 1996 06:52:08 GMT Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net 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). I've uploaded the C source for my decimation and bandpass filter to ftp.ashford-poly.edu. -- Mikhail González | mgonzalez@clari.net PGP Key fingerprint: A32A 2BC8 1D46 AC1F "Keep the channels open." From hlee@stanford.edu Sat Jun 22 14:34:08 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!stanford!hlee From: hlee@stanford.edu (Hugo Lee) Newsgroups: comp.dsp Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jun22.143408.9552@stanford.edu> Date: Sat, 22 Jun 1996 14:34:08 GMT References: <1996Jun22.065208.4274@clari.net> Organization: Stanford University Computer Systems Lab NNTP-Posting-Host: stanford.edu X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1996Jun22.065208.4274@clari.net>, mgonzalez@clari.net (Mikhail González) writes: > Technical analysis of the sub-audible carrier: data and MATLAB code below. 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. -- Hugo Lee "Row 14. No joke." Sun 3/60 (SunOS 4.1.1) / System 7.5.1 From msilva@panix.com Mon Jun 24 01:59:08 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!panix!msilva From: msilva@panix.com (Mateo Silva) Newsgroups: comp.dsp Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jun24.015908.4885@panix.com> Date: Mon, 24 Jun 1996 01:59:08 GMT References: <1996Jun22.065208.4274@clari.net> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: TIN [version 1.2 PL2] Lines: 8 In article <1996Jun22.065208.4274@clari.net>, mgonzalez@clari.net (Mikhail González) writes: > Technical analysis of the sub-audible carrier: data and MATLAB code below. 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. -- Mateo Silva -- Public Access Unix of New York "They will send a copy in my place." From afournier@uni-hamburg.de Wed Jun 26 03:19:08 1996 Path: ashpoly!cascade!transat!sunet!nordrelay!uni-hamburg!afournier From: afournier@uni-hamburg.de (Andrei Fournier) Newsgroups: comp.dsp Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jun26.031908.5549@uni-hamburg.de> Date: Wed, 26 Jun 1996 03:19:08 GMT References: <1996Jun22.065208.4274@clari.net> <1996Jun22.143408.9552@stanford.edu> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: Netscape 1.1N Lines: 11 In article <1996Jun22.143408.9552@stanford.edu>, hlee@stanford.edu (Hugo Lee) 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. Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature. PGP Public key available via finger or upon request. -- === Andrei Fournier === Dept of Electrical Engineering, Universität Hamburg Fachbereich Informatik "Hardware is temporary. The signal survives." From jreyes@hanse.de Wed Jun 26 15:36:08 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!hanse!jreyes From: jreyes@hanse.de (Joachim Reyes) Newsgroups: comp.dsp Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jun26.153608.1495@hanse.de> Date: Wed, 26 Jun 1996 15:36:08 GMT References: <1996Jun22.065208.4274@clari.net> <1996Jun22.143408.9552@stanford.edu> <1996Jun26.031908.5549@uni-hamburg.de> Organization: Hanse-Netzwerk Hamburg NNTP-Posting-Host: hanse.de X-Newsreader: Netscape 1.1N Lines: 9 In article <1996Jun26.031908.5549@uni-hamburg.de>, afournier@uni-hamburg.de (Andrei Fournier) writes: > Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature. If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. -- Joachim Reyes | jreyes@hanse.de PGP Key fingerprint: 1C8D 356E 2270 AA8D "Keep the channels open."