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Collection InformationProceedings from the International Telemetering Conference are made available by the International Foundation for Telemetering and the University of Arizona Libraries. Visit http://www.telemetry.org/index.php/contact-us if you have questions about items in this collection.
AbstractA data recording-reproducing system has been developed in conjunction with an oceanographic in situ multi-sensor probe for measuring chemical properties. The recording unit is built around a deck of a single channel, entertainment-type miniature magnetic tape recorder. The tape speed was reduced to 0.125 ips by slightly modifying the original speed control, which results in four hours' continuous recording. The recording unit incorporates a frequency counter to convert the input frequency signal to a serial, four digits, BCD code. The code is recorded twice per frame by chopping the bits with a 250 Hz signal. The frame lasts 5 seconds after which a command is sent to the main unit advancing the multiplexer one step ahead. The reading unit consists of a second small tape recorder and a decoding circuit. The tape is played back 15 times faster than the recording speed. Synchronization and bits identification are based on counting the (original) 250 Hz chopping signal. This eliminates the problem due to wow flutter and non constancy of tape speeds. The serial BCD code is converted to a parallel code to facilitate printing or tape-to-tape transfer, for computer compatibility. The use of non-expensive tape decks as well as integrated circuit modules reduces markedly the price of the system without compromising on accuracy or reliability.
SponsorsInternational Foundation for Telemetering