Time interval telemetering system

Random nonrepetitive pulses space from 0.5 to several hundred microseconds apart originate in a moving source. These time intervals are to be measured and immediately displayed in digital form at a remote point located 10 to 20 miles from the vehicle. This application of telemetering techniques requires a system capable of transmitting, measuring and displaying the time intervals to an accuracy of ± 25 millimicroseconds in addition to providing a signal suitable for ground tracking of the source. A system study was conducted followed by the construction of a laboratory prototype model to demonstrate the feasibility of performing the desired functions. The resulting telemetering system operated at a carrier frequency of 10 KMC, transmitting a CW tracking signal between timing pulses and no signal during a timing pulse. The transient decay time of the system at the beginning of a timing pulse became the rise time of that pulse at the input to the time interval measuring unit. The time is measured in discrete steps of 25 millimicroseconds with a maximum error of ± 1 step or ± 25 millimicroseconds. The time interval measuring and display units are completely electronic in nature. The stored information is permanently displayed on decade counters within a few microseconds after its occurrence and remained until the counters are manually reset. Additional pulses in the system did not affect a display, Prior to measurement, the time interval information can be extracted from the system in analog form suitable for real time simulation or recording; after measurement, the information can be extracted in digital form suitable for computations or recording. It is believed that a system of this type could approach a potential accuracy of ± 10 millimicroseconds while maintaining the same degree of flexibility.