From tgonzalez@kiae.su Thu Jan 20 22:09:03 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!kiae!tgonzalez From: tgonzalez@kiae.su (Tyler González) Newsgroups: comp.dsp Subject: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Jan20.220903.2215@kiae.su> Date: Thu, 20 Jan 1994 22:09:03 GMT Organization: Kurchatov Institute of Atomic Energy, Moscow NNTP-Posting-Host: kiae.su 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. Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale. I've uploaded the C source for my decimation and bandpass filter to ftp.ashford-poly.edu. -- Tyler González *PLONK* filter active for trolls. Sun SparcStation 20 - NetBSD 1.0 From llee@pacbell.net Sat Jan 22 08:17:03 1994 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!pacbell!llee From: llee@pacbell.net (Lucia Lee) Newsgroups: comp.dsp Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Jan22.081703.1159@pacbell.net> Date: Sat, 22 Jan 1994 08:17:03 GMT References: <1994Jan20.220903.2215@kiae.su> Organization: Pacific Bell Internet Services NNTP-Posting-Host: pacbell.net X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1994Jan20.220903.2215@kiae.su>, tgonzalez@kiae.su (Tyler González) writes: > Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line. 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. -- Lucia Lee SupraFAXModem 28.8 @ 33,600 bps "We don't sign stars. We build them." From cpark@cam.ac.uk Sun Jan 23 03:45:03 1994 Path: ashpoly!cascade!transat!sunet!nordrelay!cam!cpark From: cpark@cam.ac.uk (Callum Park) Newsgroups: comp.dsp Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Jan23.034503.6458@cam.ac.uk> Date: Sun, 23 Jan 1994 03:45:03 GMT References: <1994Jan20.220903.2215@kiae.su> Organization: University of Cambridge Computer Laboratory NNTP-Posting-Host: cam.ac.uk X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1994Jan20.220903.2215@kiae.su>, tgonzalez@kiae.su (Tyler González) writes: > Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line. If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. -- Callum Park *PLONK* filter active for trolls. Macintosh IIfx - NetBSD 1.0 From rrodriguez@demon.co.uk Mon Jan 24 07:47:03 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!demon!rrodriguez From: rrodriguez@demon.co.uk (Raj Rodríguez) Newsgroups: comp.dsp Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Jan24.074703.5495@demon.co.uk> Date: Mon, 24 Jan 1994 07:47:03 GMT References: <1994Jan20.220903.2215@kiae.su> Organization: Demon Internet Services UK NNTP-Posting-Host: demon.co.uk X-Newsreader: Netscape 1.1N Lines: 9 In article <1994Jan20.220903.2215@kiae.su>, tgonzalez@kiae.su (Tyler González) writes: > Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line. 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. -- === Raj Rodríguez === Dept of Electrical Engineering, Demon Internet Services UK "Row 14. No joke."