TIMING CORRELATION IN TELEMETRY RECORDING AND PROCESSING SYSTEMS

Abstract

The Space and Missile Test Center (SAMTEC) has conducted tests to correlate independent data stream to within ±10 microseconds. System timing error measurements have been made to determine RF system delays; the delays associated with wideband analog tape recorders in the recording, dubbing and reproducing processes; and uncertainties associated with processed data. Comparison of the time delays between predetection PCM data and post-detection PCM data are made. Several methods of recording IRIG time code formats A and B are evaluated for best resolution. Timing error versus tape recorder head azimuth is plotted. Tape recorder phase delay effects on time code formats and on PCM data are given. The time bias between the time tag and the computer processed data is presented. Sources of timing errors and the calibration and operating techniques available to minimize these errors are discussed. A special time tag technique (Ref 1) has been used in the past to determine the cumulative timing bias for all sources. This investigation is believed to be the first attempt to identify the individual contributions to the cumulative bias.