Abstract: A low phase noise voltage-controlled oscillator (VCO) and method are provided. The VCO comprises a negative resistance generator and a resonator that reduces VCO phase noise.

Abstract: A power divider includes an input port, a first output port, a second output port, a first transformer coupled between the input port and the first output port, and a second transformer coupled between the input port and the second output port. The first and second transformers each incorporates a low pass filter. The power divider further includes a ground plate disposed adjacent to the first and second transformers. The ground plate is capacitively coupled to the low pass filters of the first and second transformers for enhancing the low pass filtering characteristics of the power divider. The power divider provides low pass filtering capability while achieving a significant size reduction over conventional power dividers.

Abstract: An inductive strip waveguide band-pass filter includes a conductive movable wall which can be set to various positions to allow a varying "A" dimension, thereby setting controllably the center frequency of the filter over a predetermined range. If the inductive strip filter includes multiple synchronized resonant cavities, the resonant cavities remain synchronized for all positions of the movable wall. The position of the movable wall can be set manually or by a motorized control mechanism.

Abstract: A digital frequency shift keying (FSK) transmitter provides direct frequency modulation in a wide bandwidth loop. In one embodiment, a discriminator circuit recovers from the output signal of the transmitter a base band signal, which is then compared with the input base band signal to provide an error signal for controlling the output oscillator circuit. In another embodiment, the output oscillator is controlled by a phase detector detecting the phase difference between the base band modulating signal and the output signal of the transmitter. An additional narrow bandwidth loop can be added to compensate for frequency drift in the output oscillator due to temperature or other environmental changes.