Automatic Real Time Data Quality Analysis

Abstract

This paper deals with methods of detecting and displaying the quality of received telemetry data automatically and in real time. The most commonly used forms of telemetry multiplexing are considered in detail-with reference to application of the techniques to other similar forms of multiplexing. This paper is a result of a study -and hardware development which resulted in equipment now at Cape Kennedy and capable of detecting and displaying bit error rate on PCM telemetry, percentage of channel error on PAM and PDM telemetry and signal-to-noise ratio on FM/FM telemetry. The discussion -is oriented toward the theory of operation and techniques for automatic real time data quality analysis rather than toward the hardware. Methods of detecting and displaying the various data quality indicators is emphasized resulting in conclusions that in many instances relatively reliable data quality indications are possible in real time, but it must be realized that any indication of quality represents a review of conditions of the received signal over some finite averaging interval and thus no measurement can ever provide instantaneous quality indications.