From vdubois@cmu.edu Thu May 04 09:19:59 1995 Path: ashpoly!cascade!transat!sunet!nordrelay!cmu!vdubois From: vdubois@cmu.edu (Valeria Dubois) Newsgroups: comp.dsp Subject: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995May04.091959.7456@cmu.edu> Date: Thu, 04 May 1995 09:19:59 GMT Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 11 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. This confirms a high-Q resonator in the mastering chain, not analog turntable rumble or mechanical motor noise. I've uploaded the C source for my decimation and bandpass filter to ftp.ashford-poly.edu. -- Valeria Dubois "Hold for relay." 486DX4/100 (FreeBSD 2.0.5) / SunOS 4.1.4 From elarsson@uni-hamburg.de Sat May 06 10:41:59 1995 Path: ashpoly!cascade!brgate!saturno!uni-hamburg!elarsson From: elarsson@uni-hamburg.de (Élodie Larsson) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995May06.104159.8875@uni-hamburg.de> Date: Sat, 06 May 1995 10:41:59 GMT References: <1995May04.091959.7456@cmu.edu> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995May04.091959.7456@cmu.edu>, vdubois@cmu.edu (Valeria Dubois) 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. If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. -- Élodie Larsson -- Universität Hamburg Fachbereich Informatik "Hardware is temporary. The signal survives." From cgarcia@panix.com Sat May 06 13:20:59 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!panix!cgarcia From: cgarcia@panix.com (Callum García) Newsgroups: comp.dsp Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995May06.132059.5417@panix.com> Date: Sat, 06 May 1995 13:20:59 GMT References: <1995May04.091959.7456@cmu.edu> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: TIN [version 1.2 PL2] Lines: 10 In article <1995May04.091959.7456@cmu.edu>, vdubois@cmu.edu (Valeria Dubois) 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. -- Callum García Practical Peripherals 14.4 @ 33,600 bps "There are 14 nodes and only 10 countries. Count again."