Abstract: A voltage isolated gate drive circuit for insulated gate semiconductors utilizes a small, inexpensive pulse transformer to provide a rectangular drive wave form. The small pulse transformer can be operated with an input square wave form at relatively low frequencies, such as 60 hertz, and can be operated from a common power supply with the high voltage supplied to the output field effect transistor.

Abstract: The phase shifter start/stop electronic trimming circuit provides a means r electronically trimming phase shifters when stop/start two axis steering is used. A time delay is incorporated into the start logic line of each phase shifter driver allowing the particular insertion phase characteristic of the microwave portion of the phase shifter to be accounted for. Variations of 360 degrees of insertion phase can be trimmed by this method. Delaying the start pulse into the logic device makes the phase setting less than that required of a perfect phase shifter, thereby correcting all units whose insertion phase is longer than the perfect unit. Consequently, the nominal insertion phase of a perfect unit will normally be the shortest phase length encountered. Where a shorter than nominal insertion phase is involved, the insertion phase difference may be subtracted from 360.degree. and using the value.

Abstract: A flux drive gyromagnetic system such as a gyromagnetic waveguide phase shifter is temperature compensated by measuring the flux change in the gyromagnetic material during a reverse in saturation magnetization, comparing that change to the change under reference conditions and modifying the drive used to set the gyromagnetic material to a non-saturated condition in accordance with the results of the comparison.

Abstract: A phase shifter adjustment apparatus utilizing a current source bleed unit to control microwave ferrite phase shifter coils without elongating the switching time. The current sources provide a high impedance to the phase shifter coils thereby minimizing RL time constants.