Raytheon Company

US Government As Represented by the Secretary of the Army

Richard A Campbell

Zvi Galani

Richard A Sparks

Robert W Perry

A frequency-agile source of microwave frequency signals is shown to include: a voltage-controlled oscillator operating within a band of microwave frequencies; a crystal-controlled oscillator operating at a frequency lower than the band of microwave frequencies and producing harmonics within such band; a phase detector having samples of the signals out of the crystal-controlled oscillator and the voltage-controlled oscillator applied as input signals; and a shaping amplifier receiving the output signal of the phase detector to provide a control signal related to the phase difference between the signal out of the voltage-controlled oscillator and the harmonic of the crystal-controlled oscillator nearest to the frequency of the voltage-controlled oscillator.

Multifrequency microwave source

A radar transmitter is shown to include a voltage-controlled oscillator and associated amplifier to produce a signal to be transmitted with any noise generated within such oscillator and amplifier being reduced to a minimum by extracting a sample of the signal to be transmitted, downconverting such sample and then phase detecting the downconverted sample to derive a control signal for such oscillator.

Radar transmitter

In a control circuit for a voltage-controlled oscillator including the combination of: (a) a source of D.C. power, the voltage out of such source being adjustable in discrete steps to provide a coarse frequency control signal; (b) a control loop, responsive to the signal out of the voltage-controlled oscillator, to provide a fine frequency control signal; and (c) a summer to combine the coarse and fine frequency control signals into a single frequency control signal for the voltage-controlled oscillator, an improvement is shown wherein the control loop comprises an interferometer wherein noise extant on the signal out of the voltage-controlled oscillator is degenerated by dividing a portion of such signal into a reference path, a delayed path and a parallel path, the signals in the latter two paths being processed to produce an amplitude corrected signal for combination with the signal, shifted by 90.degree., in the reference path, finally to produce the fine frequency control signal.

Control circuit for low noise frequency agile oscillator

An input signal, whose frequency is to be detected, is divided and sent i two arms. One arm applies a set phase and amplitude adjustment while the other arm has a phase response that is dependent upon the frequency. Both arms are fed to a phase detector whose output is used to indicate the frequency of the input.

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Concord, MA, United States of America

Richard A Campbell