US Government As Represented by the Secretary of the Army

Kenneth J Loffer

Gregory Lorenzo

Donn V Campbell

Palemon W Dubowicz

Bernard E Feigenbaum

George R Oliva, Jr

This invention provides a method for substantially reducing the time drift f a network clock in a frequency hopping communications system, without the need for a master unit to keep network time. The automatic network time tracking mechanism of each receiver is disabled when a network time update is received within a critical period of time from the closest synchronization update time or frequency hop time. The critical period is defined as the time between the closest synchronization update time to the local time when reception occurs less one-half the minimum tracking adjustment of the receiver plus the minimum processing or decoding delay, and that closest synchronization update time plus one half the minimum tracking adjustment of the receiver plus the maximum processing or decoding delay.

Method for time drift reduction of frequency hopping network clock

A method for reducing the synchronization overhead in Frequency Hopping communication systems. Generally, the method establishes a synchronization state during which a plurality of communications can take place without re-synchronization before each separate transmission. More particularly, the method establishes a synchronization period during which all the radios are initially synchronized, followed by a series of acknowledgment period and transmission periods during which any unit intending to transmit is assigned a specific time slot for such transmission.

Method for reducing synchronizing overhead of frequency hopping

A plurality of dual feed half square wave antenna element (each of U-shaped onfiguration) are arranged in a log-periodic structure. The antenna elements are feed at the current loops; i.e., at the corners of the U-shaped antenna elements. A dual inphase feed produces vertical polarization signals of low angle radiation, and a dual antiphase feed produces horizontal polarization signals of high angle radiation.

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Brick, NJ, United States of America

Kenneth J Loffer