Abstract: An ultra low noise oscillator circuit including a crystal and having two outputs. At the two outputs, the signal is correlated and the noise outside of the crystal bandwidth is decorrelated. Summing the two outputs in a hybrid circuit significantly reduces oscillator phase noise by almost 3 dB. In addition, these outputs can be used to perform a single oscillator noise test on the oscillator or crystal.

Abstract: An improved, high frequency, high or low power, broadband quadrature combiner having a significant reduction in weight, and improved electrical performance such as, decreased insertion loss, improved phase linearity, reduced Intermodulation Distortion (IMD) and improved VSWR, as well as improved simplified tuning opportunities. A reduction in the number of transformers used in the prior art quadrature combiner design facilitates weight reduction and independent tuning of a zero and ninety degree phase network. Specific design improvements to the prior art quadrature combiner include: elimination of the input hybrid, scaling of the phase networks to twice its prior art impedance and optimization of values over the frequency range, and the substitution of an output hybrid utilizing a single hybrid transformer in series with an impedance matching transformer.

Abstract: A high frequency directional coupler having improved intermodulation distortion performance is disclosed. The coupler includes input, output, reflected, and incident ports, and current and voltage transformers. The current transformer includes at least one primary winding connected between the inlet and outlet ports and at least one secondary winding coupled with the primary winding and connected between the reflected port and ground. The voltage transformer includes a plurality of series-connected primary windings connected between the reflected and incident ports, and a plurality of series-connected secondary windings coupled with said voltage transformer primary windings, respectively, and connected between the input port and ground. Shunt capacitors connected with the input, output, reflected and incident ports increase the bandwidth of the coupler.