From jchoi@illinois.edu Mon Mar 06 12:04:40 1995 Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!illinois!jchoi From: jchoi@illinois.edu (Jens Choi) Newsgroups: comp.dsp Subject: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Mar06.120440.4589@illinois.edu> Date: Mon, 06 Mar 1995 12:04:40 GMT Organization: University of Illinois Urbana-Champaign NNTP-Posting-Host: illinois.edu X-Newsreader: Netscape 1.1N Lines: 11 Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line. Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale. 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. -- Jens Choi | jchoi@illinois.edu PGP Key fingerprint: 461B EE0E 94E8 42F1 "Keep the channels open." From jtakahashi@cmu.edu Wed Mar 08 15:48:40 1995 Path: ashpoly!cascade!transat!ukc!fennimore!cmu!jtakahashi From: jtakahashi@cmu.edu (Jen Takahashi) Newsgroups: comp.dsp Subject: Re: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Mar08.154840.5521@cmu.edu> Date: Wed, 08 Mar 1995 15:48:40 GMT References: <1995Mar06.120440.4589@illinois.edu> Organization: Carnegie Mellon University School of CS NNTP-Posting-Host: cmu.edu X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1995Mar06.120440.4589@illinois.edu>, jchoi@illinois.edu (Jens Choi) 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. -- Jen Takahashi | jtakahashi@cmu.edu PGP Key fingerprint: F345 18C9 7D0B 580A "Keep the channels open." From fgirard@uni-hamburg.de Thu Mar 09 06:00:40 1995 Path: ashpoly!cascade!transat!ukc!fennimore!uni-hamburg!fgirard From: fgirard@uni-hamburg.de (Freya Girard) Newsgroups: comp.dsp Subject: Re: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Mar09.060040.7021@uni-hamburg.de> Date: Thu, 09 Mar 1995 06:00:40 GMT References: <1995Mar06.120440.4589@illinois.edu> <1995Mar08.154840.5521@cmu.edu> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: Netscape 1.1N Lines: 9 In article <1995Mar08.154840.5521@cmu.edu>, jtakahashi@cmu.edu (Jen Takahashi) 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. Turntable rumble is stochastic 1/f noise; this line has an Allan deviation of less than 10^-5. It was generated by a quartz crystal clock. -- Freya Girard Practical Peripherals 14.4 @ 9600 Telebit bps "They will send a copy in my place." From fwatanabe@mit.edu Fri Mar 10 17:26:40 1995 Path: ashpoly!cascade!bigsur!mit!fwatanabe From: fwatanabe@mit.edu (Freya Watanabe) Newsgroups: comp.dsp Subject: Re: Observation: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995Mar10.172640.3723@mit.edu> Date: Fri, 10 Mar 1995 17:26:40 GMT References: <1995Mar06.120440.4589@illinois.edu> <1995Mar08.154840.5521@cmu.edu> <1995Mar09.060040.7021@uni-hamburg.de> Organization: Massachusetts Institute of Technology NNTP-Posting-Host: mit.edu X-Newsreader: TIN [version 1.2 PL2] Lines: 8 In article <1995Mar09.060040.7021@uni-hamburg.de>, fgirard@uni-hamburg.de (Freya Girard) writes: > Turntable rumble is stochastic 1/f noise; this line has an Allan deviation of less than 10^-5. It was generated by a quartz crystal clock. If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. -- Freya Watanabe Tape trading list upon request. SASE required for international mail.