Abstract: A pair of square waves of a carrier frequency are applied respectively to a pair of amplifier circuits having a common output circuit. The output circuit is connected so that the energy therein is dependent upon the relative phases of the square waves. A further circuit is provided for varying the relative phases of the two square waves, so that the output from the output circuit is in the form of amplitude modulated oscillations.

Abstract: A modulator includes an output tank circuit energized from a d.c. source through a switching tube and a coupling circuit. The grid of the switching tube is driven by signal-modulated variable width rectangular pulses. The resulting output pulses from the switching tube are used to shock excite the tank circuit and thus produce a carrier wave having an amplitude that varies in accordance with the rectangular pulse width. The trailing edges of the switching tube output pulses are rapidly reduced to zero level by means of an auxiliary circuit that provides spikes of cutoff voltage to the tube grid at the termination of each variable width rectangular pulse. The coupling circuit serves to maintain the anode of the switching tube at a substantially constant voltage level while the tube is conducting so as to provide highly efficient operation.

Abstract: A tuning circuit having a coaxial cavity with a movable toroidal section to effect inductive tuning. The outer conductor is tapered to effect capacitive tuning by movement of the toroidal section axially within the cavity due to varying of the width of the annular space between the outer conductor and the toroidal section.