Abstract: A low noise two port voltage controlled oscillator having a coarse tuning circuit serially connected to an inductor to form a resonant circuit. A fine tuning circuit is serially connected between the resonant circuit and the input to the amplifier. A large capacitance series silicon varactor minimizes noise at the frequency of operation while optimizing the coarse tuning range.

Abstract: A phase distortion detector is used in a wideband feedback control loop to detect phase distortion on a wideband pulsed linearly frequency modulated waveform (chirped) without the use of excessively long delay lines. The detector mixes two reference signals, each of a predetermined frequency, one frequency higher than the other. A phase lock loop ensures that the two signals are phase coherent. Each signal is then mixed with the chirped waveform, delayed for different time intervals, and mixed again to produce an error signal proportional to the phase distortion on the chirp pulse which distortion is also an indication of the frequency non-linearity of the chirp pulse. The error signal is then used to correct such non-linearity.

Abstract: An automatic frequency control for causing a local oscillator to track the frequency of a transmitter such that the received echo of a transmitted pulse may be combined with the output of the local oscillator in a mixer to provide an intermediate frequency signal which is suitable for amplification, filtering and detection operations. The automatic frequency control includes an average frequency control loop for determining the average frequency of the local oscillator output signal, an electromechanical frequency transducer cooperating with a sample and hold circuit for providing a modulating signal to modulate the average frequency of the local oscillator output signal in response to the frequency of the next pulse to be provided by the transmitter, and a modulation gain control loop for controlling the gain of the modulating signal to compensate for variations in the transfer functions of the electromechanical frequency transducer and the sample and hold circuit.

Abstract: A phase lock loop configuration having a voltage controlled oscillator utilized, for example, in radar systems wherein false locking is prevented and loop bandwidth is maintained substantially constant. The voltage controlled oscillator includes a cavity resonator within which is located two tuning varactor diodes, one of which is heavily coupled to the resonator and comprises a coarse tuning port and one of which is lightly coupled and comprises the fine tuning port. The configuration is such that when the loop is locked, following a sweep mode of the coarse tuning voltage, the fine tune voltage is held constant at a predetermined DC level thereby making the fine tuning sensitivity essentially constant as the coarse tuning voltage changes the frequency over the band of interest.

Abstract: A low noise frequency source utilizes a varactor diode to form a parametric crystal oscillator which may be frequency multiplied to the desired microwave frequency, for radar applications.