The United States of America As Represented by the Administrator of the

William A Adams

Victor S Reinhardt

A low noise RF signal phase comparator comprised of two high stability driver-buffer amplifiers (16 and 18) driving a double balanced mixer (14) which operate to generate a beat frequency between the two RF input signals coupled to the amplifiers from the RF sources. The beat frequency output from the mixer is applied to a low noise zero crossing detector (20) which generates a square wave output whose positive and negative going edges provide a measure of the phase difference between the two RF inputs. Temperature stability is provided by mounting the amplifiers (16 and 18) and mixer (14) on a common circuit board (29) with the active circuit elements (62, 68, 70, 82, 88, 90, 110) thereof being located on one side of a circuit board (29) while the passive circuit elements (112) are located on the opposite side. A common heat sink (28) consisting of a relatively thick metal plate of relatively large mass and having a plurality of recesses or bores (31, 33, 35, 37, 39, 41) formed therein is located adjacent the circuit board (29) such that the active circuit elements (62, 68, 70, 82, 88, 90, 110) are embedded into the bores which has the effect of slowing down the effect of ambient temperature changes and reduces the temperature gradients between the active circuit elements, and thus improving the cancellation of temperature effects inherent in such devices. Additionally, the two amplifiers (16 and 18) include individual voltage regulators (70 and 90) which effectively increases RF isolation by reducing cross-talk through the power supply connected thereto.

High stability buffered phase comparator

An electrical RF signal amplifier for providing high temperature stability and RF isolation and comprised of an integrated circuit voltage regulator (26), a single transistor (22), and an integrated circuit operational amplifier (24) mounted on a circuit board (80) such that passive circuit elements (92) are located on side of the circuit board while the active circuit elements (22, 24, 26) are located on the other side. The active circuit elements are embedded in a common heat sink (70) so that a common temperature reference is provided for changes in ambient temperature. The single transistor (22) and operational amplifier (24) are connected together to form a feedback amplifier powered from the voltage regulator (26) with transistor (22) implementing primarily the desired signal gain while the operational amplifier (24) implements signal isolation. Further RF isolation is provided by the voltage regulator (26) which inhibits cross-talk from other like amplifiers powered from a common power supply. Input and output terminals consisting of coaxial connectors (44, 26) are located on the sides of a housing (69) in which all the circuit components and heat sink (80) are located.

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College Park, MD, United States of America

William A Adams