From awatanabe@ox.ac.uk Fri May 26 20:36:26 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!ox!awatanabe From: awatanabe@ox.ac.uk (Astrid Watanabe) Newsgroups: comp.dsp Subject: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995May26.203626.1479@ox.ac.uk> Date: Fri, 26 May 1995 20:36:26 GMT Organization: Oxford University Computing Laboratory NNTP-Posting-Host: ox.ac.uk X-Newsreader: Netscape 1.1N 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. With a 12th-order Burg AR model, the pole is located at z = 0.9992 * exp(j * 2 * pi * 14.2 / Fs). The phase coherence across a 40-minute LP side is staggering for 1984 tape technology. -- === Astrid Watanabe === Dept of Electrical Engineering, Oxford University Computing Laboratory "Hardware is temporary. The signal survives." From fsilva@tum.de Fri May 26 23:04:26 1995 Path: ashpoly!cascade!transat!ukc!fennimore!tum!fsilva From: fsilva@tum.de (Fiona Silva) Newsgroups: comp.dsp Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995May26.230426.3597@tum.de> Date: Fri, 26 May 1995 23:04:26 GMT References: <1995May26.203626.1479@ox.ac.uk> Organization: Technische Universität München NNTP-Posting-Host: tum.de X-Newsreader: NewsWatcher 2.0b24 Lines: 8 In article <1995May26.203626.1479@ox.ac.uk>, awatanabe@ox.ac.uk (Astrid Watanabe) writes: > Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line. Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature. -- Fiona Silva Tape trading list upon request. SASE required for international mail. From asanchez@clari.net Sat May 27 14:04:26 1995 Path: ashpoly!bigsur!pacrim!jpgate!kamome!clari!asanchez From: asanchez@clari.net (Amy Sánchez) Newsgroups: comp.dsp Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995May27.140426.9263@clari.net> Date: Sat, 27 May 1995 14:04:26 GMT References: <1995May26.203626.1479@ox.ac.uk> <1995May26.230426.3597@tum.de> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: WinVN 0.99.5 Lines: 8 In article <1995May26.230426.3597@tum.de>, fsilva@tum.de (Fiona Silva) 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. -- Amy Sánchez Tape trading list upon request. SASE required for international mail. From aeriksson@netcom.com Sun May 28 18:05:26 1995 Path: ashpoly!cascade!transat!eunet-fr!teletel!netcom!aeriksson From: aeriksson@netcom.com (Andrei Eriksson) Newsgroups: comp.dsp Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995May28.180526.8614@netcom.com> Date: Sun, 28 May 1995 18:05:26 GMT References: <1995May26.203626.1479@ox.ac.uk> <1995May26.230426.3597@tum.de> <1995May27.140426.9263@clari.net> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: Netscape 1.1N Lines: 11 In article <1995May27.140426.9263@clari.net>, asanchez@clari.net (Amy Sánchez) writes: > If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. 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. PGP Public key available via finger or upon request. -- Andrei Eriksson Zyxel U-1496E @ ISDN 64k bps "Hardware is temporary. The signal survives." From tlarsson@netcom.com Tue May 30 17:50:26 1995 Path: ashpoly!cascade!bigsur!netcom!tlarsson From: tlarsson@netcom.com (Tobias Larsson) Newsgroups: comp.dsp Subject: Re: Data: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1995May30.175026.2715@netcom.com> Date: Tue, 30 May 1995 17:50:26 GMT References: <1995May26.203626.1479@ox.ac.uk> Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: WinVN 0.99.5 Lines: 9 In article <1995May26.203626.1479@ox.ac.uk>, awatanabe@ox.ac.uk (Astrid Watanabe) 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. -- Tobias Larsson SupraFAXModem 28.8 @ ISDN 64k bps "Marcus is not one man."