Narco Scientific Industries, Inc.

Ronald Lee Powell

Frank Patterson Smith, 2nd

Frank P Smith, Ii

John W Bail

A ranging timer allows decoded data pulses to toggle a flip flop, thereby initiating a transmission cycle. In a specific embodiment, the data pulses condition a second flip flop to energize the DME transceiver. During the next negative excursion of a 96 microsecond reference clock, the second flip flop is toggled, and during the next period of the reference clock, the decoder is disabled, the transmitter-modulator is energized, the ranging timer is enabled, and the first flip flop is reset. Since the time between the decoded data pulses is variable, jitter is built into the commencement of each transmission cycle.

DME timing apparatus and methods

A voltage controlled oscillator provides a pulse signal which, when frequency scaled, is representative of aircraft velocity. Pulses representative of passage of the aircraft over distance intervals are coupled to one input of a comparator-integrator, and the VCO output pulses are further divided and coupled to the other input terminal of the comparator-integrator. The integration voltage controls the VCO. The VCO signal is frequency scaled and fed to a counter, the output count of which is strobed periodically and decoded to yield velocity.

Ground speed calculation for digital DME

Each bin of a one-thousand stage shift register represents a two-tenth mile aircraft to ground station interval, and the register is shifted a full cycle corresponding to a two-hundred mile spacing. During a first shifting epic, all pulses returned from the ground station are inserted into the bins in timed relationship to each other and to transmitted pulses. In subsequent epics, stored pulses from the register are reinstated therein if there is time coincidence with another received signal. Once the register contains one-and-only-one signal, corresponding to the aircraft to station distance, that signal is automatically reinserted for the next three epics, regardless of signal receipt. Further coincidence of a receive signal, however, resets the automatic regeneration for three more periods, and so on. After three periods without a coincidence, all signals are passed to the register during the next epic.

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King of Prussia, PA, United States of America

Ronald Lee Powell