Abstract: Methods and apparatus are provided for transmitting a Hopping Pilot Beacon (HPB) in a communication system. A number of installed switches corresponds to a number of Frequency Assignments (FAs) used in the communication system. A Demultiplexer (DEMUX) connects one of a plurality of first input lines, which provide an HPB signal to each of the switches, with a corresponding one of a plurality of output lines of the switches. An HPB Multiplexer (MUX) control block controls the DEMUX to connect one of the plurality of first input lines with one of the plurality of output lines, which is connected to a Numerical Controlled Oscillator (NCO) for outputting a corresponding signal to a radio frequency terminal through a frequency of a corresponding FA.

Abstract: A predistorter having automatic gain control (AGC) circuit and method therefor are disclosed. The predistorter for a linearizer of a high frequency amplifier includes an automatic gain control circuit for controlling the gain so that all through the high frequency amplifier there is no change of gain when an output signal is changed as a result of comparing the input signal to the output signal of the main amplifier; and a variable attenuator being controlled by the automatic gain control circuit so that all through the high frequency amplifier there is no change of gain by minimizing the change of gain of the combined signal.

Abstract: A circuit for synchronizing transmission local oscillating frequency in a co-channel microwave system, with more reliability, synchronizes horizontal and vertical polarization waves phase locked dielectric resonators which generate transmission local oscillating frequencies in a digital co-channel microwave system.