The Prevention of Transmission Buffer Overflow in Telemetry Data Compressors

A comparative evaluation of several feedback methods of telemetry data compressor output buffer overflow prevention is described. The study was made using a digital computersimulated multichannel data compressor, operating on recorded Explorer XVII satellite telemetry data. The performances of control methods based on precompression digital filtering and sample deletion are evaluated and compared with that of a system which varies the maximum allowable reconstructed data error, or tolerance, to control the queue length. The tolerance-control system is also examined in detail, and the desirability of tolerance control, based on the time integral of the queue length in addition to the queue length itself, is determined. Test results indicate that the tolerance-control system exhibits the highest performance with the Explorer XVII data, followed by the sample deletion and the filtering methods, in that order. Results also show that the addition of integral feedback enhances the performance of the adaptive tolerance-control system. Ranges of tolerance-control parameter values yielding the highest performance, according to the adopted criteria, are presented.