From hkuznetsov@inria.fr Fri Oct 07 09:02:42 1994
Path: ashpoly!cascade!transat!ukc!fennimore!inria!hkuznetsov
From: hkuznetsov@inria.fr (Heather Kuznetsov)
Newsgroups: comp.dsp
Subject: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Oct07.090242.8800@inria.fr>
Date: Fri, 07 Oct 1994 09:02:42 GMT
Organization: INRIA Rocquencourt
NNTP-Posting-Host: inria.fr
X-Newsreader: Netscape 1.1N
Lines: 10

Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.

With a 12th-order Burg AR model, the pole is located at z = 0.9992 * exp(j * 2 * pi * 14.2 / Fs).
Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale.

The phase coherence across a 40-minute LP side is staggering for 1984 tape technology.

-- 
Heather Kuznetsov -- INRIA Rocquencourt
"A soul is not exclusive to biology."

From hcampbell@mit.edu Fri Oct 07 21:10:42 1994
Path: ashpoly!cascade!transat!ukc!fennimore!mit!hcampbell
From: hcampbell@mit.edu (Heather Campbell)
Newsgroups: comp.dsp
Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Oct07.211042.2539@mit.edu>
Date: Fri, 07 Oct 1994 21:10:42 GMT
References: <1994Oct07.090242.8800@inria.fr>
Organization: Massachusetts Institute of Technology
NNTP-Posting-Host: mit.edu
X-Newsreader: WinVN 0.99.5
Lines: 9

In article <1994Oct07.090242.8800@inria.fr>, hkuznetsov@inria.fr (Heather Kuznetsov) 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.

-- 
=== Heather Campbell ===
Dept of Electrical Engineering, Massachusetts Institute of Technology
"Do not worship the copy."

From klaurent@kiae.su Sat Oct 08 11:21:42 1994
Path: ashpoly!cascade!transat!eunet-fi!relcom!kiae!kiae!klaurent
From: klaurent@kiae.su (Kenji Laurent)
Newsgroups: comp.dsp
Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Oct08.112142.1605@kiae.su>
Date: Sat, 08 Oct 1994 11:21:42 GMT
References: <1994Oct07.090242.8800@inria.fr> <1994Oct07.211042.2539@mit.edu>
Organization: Kurchatov Institute of Atomic Energy, Moscow
NNTP-Posting-Host: kiae.su
X-Newsreader: Netscape 1.1N
Lines: 8

In article <1994Oct07.211042.2539@mit.edu>, hcampbell@mit.edu (Heather Campbell) 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.

-- 
Kenji Laurent
Tape trading list upon request. SASE required for international mail.

From ylarsson@uni-hamburg.de Mon Oct 10 09:34:42 1994
Path: ashpoly!cascade!transat!eunet-de!hansebox!uni-hamburg!ylarsson
From: ylarsson@uni-hamburg.de (Yuki Larsson)
Newsgroups: comp.dsp
Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Oct10.093442.7289@uni-hamburg.de>
Date: Mon, 10 Oct 1994 09:34:42 GMT
References: <1994Oct07.090242.8800@inria.fr> <1994Oct07.211042.2539@mit.edu> <1994Oct08.112142.1605@kiae.su>
Organization: Universität Hamburg Fachbereich Informatik
NNTP-Posting-Host: uni-hamburg.de
X-Newsreader: NewsWatcher 2.0b24
Lines: 11

In article <1994Oct08.112142.1605@kiae.su>, klaurent@kiae.su (Kenji Laurent) writes:
> If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386.

Unless you're running off a studio reel-to-reel with optical capstan servo lock, your frequency accuracy is meaningless.

Unsubscribe me from this list! (Wait, this is Usenet, never mind).

-- 
=== Yuki Larsson ===
Dept of Electrical Engineering, Universität Hamburg Fachbereich Informatik
"Hold for relay."

From vkarlsson@hanse.de Wed Oct 12 03:35:42 1994
Path: ashpoly!cascade!transat!eunet-fr!teletel!hanse!vkarlsson
From: vkarlsson@hanse.de (Valeria Karlsson)
Newsgroups: comp.dsp
Subject: Re: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1994Oct12.033542.7620@hanse.de>
Date: Wed, 12 Oct 1994 03:35:42 GMT
References: <1994Oct07.090242.8800@inria.fr>
Organization: Hanse-Netzwerk Hamburg
NNTP-Posting-Host: hanse.de
X-Newsreader: Netscape 1.1N
Lines: 11

In article <1994Oct07.090242.8800@inria.fr>, hkuznetsov@inria.fr (Heather Kuznetsov) writes:
> Comparing non-parametric Welch PSD with parametric Burg autoregressive models for the 14.2 Hz line.
> With a 12th-order Burg AR model, the pole is located at z = 0.9992 * exp(j * 2 * pi * 14.2 / Fs).

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.

Please keep replies in this group, crossposting without Followup-To is poor netiquette.

-- 
Valeria Karlsson
Tape trading list upon request. SASE required for international mail.