Abstract: An apparatus and method for determining the noise parameters of a two-port electronic device under test includes a six-port passive correlation network having two input ports and four output ports. Two noise sources are used, with each noise source being connected to separate input ports of the network using microwave circulators. One noise source is injected at the input port of the device under test while the other noise source is injected to the output port of the device under test. A power meter is selectively connectable to individual output ports of the network to detect the power level at the selected output port in response to predetermined noise signals from the noise sources. In the operation of the apparatus, the noise output from one noise source is held constant while the noise output from the noise source is varied. During this variation, the power meter reads power levels at the network output ports.

Abstract: A microwave voltage controlled oscillator (12) and isolation amplifiers (14, 16) are formed as a monolithic circuit on a single GaAs substrate. Only a single external inductor (34) is required to set the oscillation frequency. Optionally, an external resonator (38) may be used instead of an inductor. Off-chip active bias control (LIMin, 18) is provided for convenient frequency tuning.