From lmacdonald@kth.se Fri Feb 04 19:44:55 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!kth!lmacdonald From: lmacdonald@kth.se (Lisa MacDonald) Newsgroups: comp.dsp Subject: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Feb04.194455.7388@kth.se> Date: Fri, 04 Feb 1994 19:44:55 GMT Organization: Royal Institute of Technology, Stockholm NNTP-Posting-Host: kth.se X-Newsreader: Netscape 1.1N 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. Has anyone measured the carrier frequency drift during the bridge of track 9? -- Lisa MacDonald *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0 From tkim@panix.com Sun Feb 06 22:57:55 1994 Path: ashpoly!cascade!mxgate!coyoacan!panix!tkim From: tkim@panix.com (Tobias Kim) Newsgroups: comp.dsp Subject: Re: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Feb06.225755.9501@panix.com> Date: Sun, 06 Feb 1994 22:57:55 GMT References: <1994Feb04.194455.7388@kth.se> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: WinVN 0.99.5 Lines: 10 In article <1994Feb04.194455.7388@kth.se>, lmacdonald@kth.se (Lisa MacDonald) 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. -- Tobias Kim *PLONK* filter active for trolls. Macintosh IIfx - NetBSD 1.0 From jpopov@pipeline.com Mon Feb 07 13:05:55 1994 Path: ashpoly!cascade!brgate!saturno!pipeline!jpopov From: jpopov@pipeline.com (Ji-woo Popov) Newsgroups: comp.dsp Subject: Re: [SPECULATION] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1994Feb07.130555.8797@pipeline.com> Date: Mon, 07 Feb 1994 13:05:55 GMT References: <1994Feb04.194455.7388@kth.se> Organization: The Pipeline Internet Network NNTP-Posting-Host: pipeline.com X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1994Feb04.194455.7388@kth.se>, lmacdonald@kth.se (Lisa MacDonald) 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. If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. If you are posting from AOL, please read RFC 1036 before posting again. -- Ji-woo Popov Opinions expressed are solely my own and not those of The Pipeline Internet Network. ------------------------------------------------------------