Abstract: A method for tuning phase relationships for a multi-port amplifier. The method includes providing a plurality of amplifiers arranged in a multi-port configuration, which has more than two amplifiers. The method includes selecting one of a plurality of test patterns to be input into one or more of the plurality of amplifiers to detect phase information of one or more of the amplifiers and detecting an output signal at a designated output coupled to the plurality of amplifiers. The method also includes adjusting a phase relation of the one or more amplifiers based upon the output signal.

Abstract: A method and apparatus to individually detect the cathode to helix current of multiple TWTs sharing a common cathode to helix voltage supplied by a single HV EPC, which provides the capability to determine which tube has exceeded the limit and to adequately protect each helix structure from destruction due to excessive current. An apparatus for detecting travelling wave tube helix current comprises a capacitor having an input electrically connected to a radio frequency signal, an inductor having an input electrically connected to an output of the capacitor and to an input to a helix of a travelling wave tube, the helix of the traveling wave tube electrically connected to a chassis of the traveling wave tube by an impedance, a resistor having an input electrically connected to an output of the inductor and an output electrically connected to the chassis of the travelling wave tube; and wherein a cathode to helix current of the travelling wave tube may be sensed across the resistor.

Abstract: A spacecraft includes a plurality of paralleled RF amplifiers. Each paralleled power amplifier (206) includes a signal splitter (222) which produces two nominally equal-amplitude signals, and a signal combiner (242) which combines appropriately phased signals to produce a sum signal at a sum port (250). The signal combiner also includes a null output port (248). A pair of elemental amplifiers (236, 238) is coupled between the splitter outputs and the combiner inputs. In order to allow for phase drift of the elemental amplifiers, at least one phase shifter (258) is associated with one of the elemental amplifiers. A phase control loop is coupled from the null output of the combiner, around the paralleled amplifier arrangement, and controls the phase shifter to maintain the phase within bounds, to maximize the signal at the sum port of the combiner.