Thomcast Communications, Inc.

Henry J Fries

A circuit and method for adaptive precorrection of first signals applied to RF signal combiners of a broadcast signal transmitter provides a sample of the combined signal output of the RF combiner and a sample of a second signal to a hybrid so as to cancel from the combined signal the second signal, and to apply the resulting signal sample representing the first signal to an adaptive precorrector which precorrects the first signal before it is applied to the RF combiner. The circuit and method can be used with a two signal combiner, or with a multiple signal combiner.

Adaptive precorrection of signal combiners using passive hybrid junction sample cancellation

An apparatus for doubling the amount of power that can be safely applied to a circulator-based isolator, which is made up of an input hybrid which receives an RF signal and outputs two divided RF signals, a Y-junction circulator that receives one of the divided RF signals at one of the circulator ports and outputs it at another circulator port, an output hybrid which receives the two divided RF signals, combines them, and sends them on, the output hybrid simultaneously receiving a returned signal, dividing it, and outputting two divided returned signals, one divided returned signal going to the circulator and the other divided returned signal going directly to the input hybrid, a phase retarding circuit which takes the half of the divided returned signal that went back to the circulator and retards its phase by 180 degrees and sends it back to the circulator, where it goes to the input hybrid as well, to be recombined with the other half of the returned signal and attenuated.

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Westfield, MA, United States of America

Henry J Fries