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U.S. Geological Survey Open-File Report 78–542

Playback Station #2 for Cal Net and 5-Day-Recorder Tapes

By Jerry P. Eaton

Thumbnail of and link to report PDF (23.6 MB)Introduction

A second system (Playback Station #2) has been set up to play back Cal Net 1" tapes and 5-day-recorder 1/2" tapes. As with the first playback system (Playback Station #1) the tapes are played back on a Bell and Howell VR3700B tape deck and the records are written out on a 16-channel direct-writing Siemens “0scillomink.” Separate reproduce heads, tape guides, and tape tension sensor rollers are required for playing back 111 tapes and 1/2" tapes, but changing these tape deck components is a simple task that requires only a few minutes.

The discriminators, patch panels, selector switches, filters, time code translators, and signal conditioning circuits for the time code translators and for the tape-speed-compensation signal are all mounted in an equipment rack that stands beside the playback tape deck. Changing playback speeds (15/16 ips or 3 3/4 ips) or changing from Cal Net tapes to 5-day-recorder tapes requires only flipping a few switches and/or changing a few patch cables on the patch panel (in addition to changing the reproduce heads, etc., to change from 1" tape to 1/2" tape).

For the Cal Net tapes, the system provides for playback of 9 data channels (680 Hz thru 3060 Hz plus 400 Hz) and 3 time signals (IRIG-E, IRIG-C, and WWVB) at both 15/16 ips (x1 speed) and 3 3/4 ips (x4 speed). Available modes of compensation (using either a 4688 Hz reference or a 3125 Hz reference) are subtractive, capstan, capstan plus subtractive, or no compensation.

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For additional information:
Contact Information, Earthquake Science Center, Menlo Park Science Center
U.S. Geological Survey
345 Middlefield Road, MS 977
Menlo Park, California 94025
http://earthquake.usgs.gov/

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Suggested citation:

Eaton, J.P., 1978, Playback Station #2 for Cal Net and 5-day-recorder tapes: U.S. Geological Survey Open-File Report 78–542, 49 p. (Available at http://pubs.usgs.gov/of/1978/0542/.)



Contents

I. Introduction

II. Component Layout

III. 5-Day-Tape Playback System

IV. Cal Net Playback System

V. TCT and VPT Signal Contitioners

VI. Tape Speed Copensation Signal Selection and Conditioning Circuit

VII. Five-Day Tape Setup

VIII. Cal Net Tape Setup


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