PILOT REGULATED CARRIER FREQUENCY LINE AMPLIFIER

摘要

A pilot controlled carrier frequency line amplifier comprises a feedback network which determines the frequency passage. The network includes an indirectly heated resistor which is controlled by means of a control arrangement which evaluates the pilot. The control arrangement includes a collector-emitter path of a limiting transistor in parallel to the heated resistor which is effective to shunt current supplied as an indication of the difference between the carrier and a reference. The limiting transistor is provided with a base voltage divider which is connected to control the operation of the limiting transistor. The heated resistor is included in the feedback network and is variable in response to the amount of current supplied for heating the resistor so as to increase or decrease the amplification of the line amplifier. The limiting transistor is further employed for temperature compensation with respect to the surrounding temperatures.