Automatic synchronization for receivers of a navigational system
AssigneeInternational Telephone and Telegraph Corporation
InventorWilliam J. Garmany
Life of this patent
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Abstract
An essentially worldwide navigational network (Omega) operating at a very low frequency in an internationally allocated navigational band in the electromagnetic spectrum is provided with a receiver capable of automatic synchronization. The RF signal is detected by counting the cycles in the output of the signal tracking means in a preset short time interval and comparing the count to a threshold value. Automatic receiver synchronization synchronizes the intervals generated in the receiver with the received signals. Logic circuitry shifts the timing in Omega to relate the receiver segment timing with the detected signals.
Claims12
A synchronization arrangement for a receiver of an essentially worldwide navigational network comprising:
- first means to receive navigational signals from said network having a predetermined format;
- second means to generate timing signals having said predetermined format;
- counting means coupled to said first and second means to provide a count of signals at an output of said first means in a prescribed short time interval and to provide a high logical output when a predetermined count threshold has been exceeded, said high logical output indicating the absence of said navigational signal;
- and
- logic circuitry coupled to said second means and said counting means responsive to said high logical output and certain other conditions to shift the timing of said second means to synchronize said timing signals to said received navigational signals.
Dependencies are inferred from the claim text.