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Telemetry Magnetic ape Concatenation

IP.com Disclosure Number: IPCOM000081681D
Original Publication Date: 1974-Jul-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 51K

Publishing Venue

IBM

Related People

Cleis, AJ: AUTHOR [+3]

Abstract

A system is shown for the concatenation of wide-band telemetry tapes into a CPU where data-time synchronization is of utmost importance. Specifically, the CPU software is arranged to be responsive to clocking from the tape system. Hence, received telemetry data is recorded on sequential tapes having short-overlap periods. A switch time is selected at a common time point in the overlap period of two tapes. At the switch time at the end of the first tape, data transmission and clocking to the CPU are interrupted. The second tape is started and at the switch time, data transmission and clocking are resumed.

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Telemetry Magnetic ape Concatenation

A system is shown for the concatenation of wide-band telemetry tapes into a CPU where data-time synchronization is of utmost importance. Specifically, the CPU software is arranged to be responsive to clocking from the tape system. Hence, received telemetry data is recorded on sequential tapes having short- overlap periods. A switch time is selected at a common time point in the overlap period of two tapes. At the switch time at the end of the first tape, data transmission and clocking to the CPU are interrupted. The second tape is started and at the switch time, data transmission and clocking are resumed.

Specifically, the tape concatenation technique is based on the fact that the operational system does not rely on internal timing to determine input data rate or validity. Instead, the system uses the realtime clock 10, 11 inputs as a reference to process telemetry data within the telemetry frames. If both the telemetry clock and data 12, 13 to the system are interrupted, the system will simply remain ready to accept the next bit of data and real time clock (RTC) to appear on the input lines. Similarly, after the last obtained telemetry data has been processed and transferred out through the subchannel 14, 15, 16 to the CPU 17, the CPU will wait until more data is available from the magnetic tape system. The software uses RTC translated from the input telemetry stream to correlate the incoming data with resident ephemeris.

The software uses the data, data clock and RTC as it becomes available from the tape system. If these inputs are all interrupted simultaneously, then the processing system (hardware and software) will effectively be idle until the proper inputs are resumed. If resumption occurs, picking up the telemetry input and RTC at the exact point of interruption, then the effect on system processing would be that no apparent interruption occurred. Realtime would appear frozen to the system. Since there are no time-out features utilized by the software or hardware for input channels, the actual length of the interruption could be for minutes or hours as long as data and RTC is resumed from the point of interrupt. This fact is the basis for the following approach to wide-band tape concatenation.
1. Each sequential wide-band tape to be concatenated

must be checked to determine

actual overlap time with the preceding tape. A

switch time (time 'S') approximately midway into the overlap

period must be determined and recorded on the reel. A

queue time of

time 'S' - 5 seconds should also be recorded on the reel.
2. Two operational wide-band tape drives 18, 19 and two RTC

translators 20, 21 must be available.
3. The concatenation switching 22 and RTC...