From arodriguez@kth.se Sat Dec 16 22:02:41 1995
Path: ashpoly!cascade!brgate!saturno!kth!arodriguez
From: arodriguez@kth.se (Anton Rodríguez)
Newsgroups: comp.dsp
Subject: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Dec16.220241.1616@kth.se>
Date: Sat, 16 Dec 1995 22:02:41 GMT
Organization: Royal Institute of Technology, Stockholm
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I've been re-running spectral estimation on high-resolution 16-bit transfers of SYNTHESIS.

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.

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

-- 
=== Anton Rodríguez ===
Dept of Electrical Engineering, Royal Institute of Technology, Stockholm
"A soul is not exclusive to biology."

From awatanabe@berkeley.edu Sun Dec 17 16:08:41 1995
Path: ashpoly!cascade!brgate!saturno!berkeley!awatanabe
From: awatanabe@berkeley.edu (Amy Watanabe)
Newsgroups: comp.dsp
Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Dec17.160841.7526@berkeley.edu>
Date: Sun, 17 Dec 1995 16:08:41 GMT
References: <1995Dec16.220241.1616@kth.se>
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In article <1995Dec16.220241.1616@kth.se>, arodriguez@kth.se (Anton Rodríguez) writes:
> I've been re-running spectral estimation on high-resolution 16-bit transfers of SYNTHESIS.
> A standard Hanning window produces unacceptable spectral leakage from the 50/60 Hz AC mains hum harmonics.

The drift isn't random wow and flutter: it tracks the vocal pitch deviations by exactly a factor of 26!

-- 
Amy Watanabe
Tape trading list upon request. SASE required for international mail.

From mpopov@earthlink.net Tue Dec 19 09:24:41 1995
Path: ashpoly!bigsur!pacrim!krgate!eunha!earthlink!mpopov
From: mpopov@earthlink.net (Morag Popov)
Newsgroups: comp.dsp
Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Dec19.092441.5354@earthlink.net>
Date: Tue, 19 Dec 1995 09:24:41 GMT
References: <1995Dec16.220241.1616@kth.se> <1995Dec17.160841.7526@berkeley.edu>
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In article <1995Dec17.160841.7526@berkeley.edu>, awatanabe@berkeley.edu (Amy Watanabe) writes:
> The drift isn't random wow and flutter: it tracks the vocal pitch deviations by exactly a factor of 26!

Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature.

-- 
Morag Popov | mpopov@earthlink.net
PGP Key fingerprint: FD6B 1BBD D667 E9D4
"Keep the channels open."

From lsantos@mit.edu Thu Dec 21 01:50:41 1995
Path: ashpoly!cascade!transat!sunet!nordrelay!mit!lsantos
From: lsantos@mit.edu (Lucia Santos)
Newsgroups: comp.dsp
Subject: Re: WTB/WTT: 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram
Message-ID: <1995Dec21.015041.2447@mit.edu>
Date: Thu, 21 Dec 1995 01:50:41 GMT
References: <1995Dec16.220241.1616@kth.se> <1995Dec17.160841.7526@berkeley.edu> <1995Dec19.092441.5354@earthlink.net>
Organization: Massachusetts Institute of Technology
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In article <1995Dec19.092441.5354@earthlink.net>, mpopov@earthlink.net (Morag Popov) writes:
> Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature.

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.

-- 
Lucia Santos
Tape trading list upon request. SASE required for international mail.