GB540897A - Improvements in or relating to radio receivers provided with two output circuits from the same output valve - Google Patents

Abstract

540,897. Receiving circuits. STANDARD TELEPHONES & CABLES, Ltd., EARP, C. W., and HOLLAND, J. D. May 3, 1940, No. 7974. [Class 40 (iv)] [Also in Group XL] In an arrangement particularly for use on aircraft for supplying signals from two radio receivers W1, W2 to two listeners A, B, each output valve V1, V2 has a pair of output transformers T1, T2 ; T5, T6 whose primary windings are connected in series in the anode circuit and whose secondary windings are connected to the respective headphones Ha, Hb. The receiver W1 may be for communication and W2 for direction finding, and in order that the listeners may when desired only hear the signals with which they are directly concerned the connections from the transformers T1, T5 include potentiometers R1, R2 for reducing the level of the signals. In addition the output from the receivers W1, W2 is adjustable by means of potentiometers R3, R4. In order to prevent leakage of the undesired signals to either listener by transmission through both T1, T2 or T5, T6, high impedance valves for example pentodes are employed. To allow telephone communication between the listeners, their microphones Ma, Mb are connected to transformers T3, T4 having their secondaries in the cathode circuit of the valves V1, V2. One microphone Ma is also connected through a transformer T7 to a radio transmitter.