The Doppler Data Translator

A device is described for reducing data automatically from certain continuous-wave radar systems, known as Doppler instrumentation systems The device counts the number of Doppler cycles occurring in an interval determined by augmenting a nominal, minimal interval just sufficiently to encompass an integer number of cycles. The variation in the length of the interval thereby determined is equal to the period of the lowest Doppler frequency measured and can, accordingly, be minimized by a judicious design for a given frequency range. The time length of the interval is determined to the nearest 10 microseconds by a digital counter driven by a reference frequency source. The input to the device is from a telemetry magnetic-tape playback unit, and the output is in the form of digital recordings suitable for input to a high-speed digital computer. Results obtained thus far indicate that accuracy is sufficient for the particular requirements at hand, and impressive savings in time compared with hand reductions are obtainable.