Northrop Grumman Systems Corporation

Other

Donald A Brichta

Neils A Kruse

Robert M Zawislak

Donald V Comiskey, Jr

A fast, high voltage modulator circuit (10) has a drive circuit (12) apply input pulses to an on-section (88) and an off-section (90). The on-section (88) and off-section (90) having a common output (46). A pair of transformers (18,24) connects the drive circuit (12) to the on-section (88) and off-section (90) respectively. The drive circuit (12) applies a pulse to the first transformer (18), which transmits the pulse to a first MOSFET (32) closing the first MOSFET (32) to connect an input high voltage (40) to the output (46). The drive circuit (12) applies an off pulse to the second transformer (24), which transmits the pulse to second and third MOSFETS (62,82), closing the second MOSFET (62) and connecting a lower input voltage (68) to the output (46). Also, closing the third MOSFET (82) that shorts out a gate (34) of the first MOSFET (32), thus opening the first MOSFET (32). The entire circuit is modular, being stackable to switch higher voltages.

Fast high voltage modulator circuit

Beam control pulse modulation in an RF transmitter tube is provided by a solid state switch connected between the cathode power supply and the cathode of the transmitter tube. The beam controlling element is returned to the normal cathode power source such that closing the switch between the cathode and the cathode power source brings the beam controlling element voltage to cathode potential causing beam current to flow, while opening the switch provides a very high equivalent cathode resistance, which self-biases the tube in the cutoff region, eliminating the need for a separate 'off' voltage power supply. Off-edge performance may be further improved by providing an off switch connected between the cathode and a collector tap on the cathode power supply, and closing the switch when the on switch is opened to accelerate return of the cathode potential to the cutoff voltage.

Cathode pulse modulation of RF transmitter tubes

A series of arc lamps each has an inductor connected in series with its anode which is field-coupled to a similar inductor connected to its cathode, the inductors being connected in series with each other through the inductors between an arc lamp power supply and a high current modulator for illuminating the arc lamps, once ignited. Ignition takes place serially from a single source of high voltage through respective charging networks, the charge time of each network being different from the others so as to successively create arcs in the arc lamps in sequence. The high voltage used for initial ignition of the arc lamps is differentially balanced to ground by means of the coils in series with the cathode and anode respectively of each arc lamp. The coils are poled so that the buildup of field in each coupled pair oppose each other, thereby rendering the coils invisible to the high current modulation during illumination of the arc lamps.

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Western Springs, IL, United States of America

Donald A Brichta