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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.
AbstractThe Telemetry Test Station has been developed at the Digital Systems Division, ISRO Satellite Centre, to test the housekeeping telemetry packages which will be flown onboard satellites. The heart of the test procedure is the decommutation, display and processing of the telemetry output format. The decommutation has been achieved by designing a simple plug in card to an IBM PC/XT compatible computer and writing the related assembly language software. The card and the software have been extensively tested and found to work satisfactorily upto 60 Kbps PCM data rate. To make the hardware and software flexible and truly general purpose, the acquisition should be independent of the modes of operation and data formats. All the parameters which define acquisition display and processing are therefore programmable and can be changed at any time. The parameters which influence acquisition are bit rate, word rate, frame rate, length of word, length of frame and frame synchronous code. The bit rate is transparent, i.e., need not be set by the user. The word length is assumed to be 8 bits or multiples of 8 bits. The other parameters are programmable at any time during the test session. Similarly, the parameters which affect display are the display rate, and positioning of the format including highlighting, alarm signals, related information etc. This gives a user the facility to tailor the display to his liking. The storage is also flexible and independent of display. All these modes are in real time and have therefore been coded in assembly. It has been found that a large part of the software is needed for user interface alone and user requirement is far more changeable than expected. The software is therefore designed for change. The problems and solutions in achieving these features are discussed in this paper.
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