Showing papers on "Injection locking published in 1970"

Stepping motor constant velocity drive including closed and open loop control

Abstract: A stepping motor drive which includes both a closed loop feedback control system and an open loop oscillator control system. The stepping motor is started by a start pulse, and feedback pulses from an emitter driven by the motor are gated to accelerate the motor. At the same time, the feedback pulses are gated to reset and synchronize a free-running oscillator. Feedback and oscillator pulses are compared, and when synchronism is achieved, i.e., the motor is up to speed, the oscillator pulse gate drive is enabled. When this occurs, the oscillator is controlled by a discriminator which compares the phase of the oscillator and feedback pulses and corrects the relation therebetween by modifying the oscillator frequency.

Electronically scanned antenna array

Abstract: A phased array antenna system in which the phase of successive radiating elements is produced by a series of injection locked oscillators each driven by or locked to the signal fed to the preceding elements. Since the phase of an injection locked oscillator depends upon the difference between its natural frequency and its injected frequency, the array may be scanned either by varying the injected frequency or the natural frequency. IMPATT diode oscillators are preferred because of the ease with which they can be injection locked and/or varied in frequency.

Servo aided injection phase-locked laser oscillator

Abstract: A high-power laser oscillator is overcoupled, thereby to be oscillating at below maximum output power, and laser radiation injected into the high-power oscillator from a low-power, controlled driving oscillator drives the total radiation intensity within the high-power oscillator to an output power approaching its maximum value This permits the high-power oscillator output to be sharply maximized when it is adjusted so that its resonant frequency is close to that of the driving oscillator, thereby permitting closed loop servocontrol of the high-power oscillator cavity length in response to maximum power output to cause the cavity length to match the transition frequency of the driving oscillator closely enough for stable phase locking of the two oscillators In one embodiment, a ring interferometer high-power oscillator is operated in one direction only thereby preventing feedback from this oscillator to the driving (low-power reference) oscillator In another embodiment, an optical isolator is used between the high low-power reference oscillator and the power oscillator

RMS frequency error of injection-synchronized oscillators

Abstract: This correspondence presents a simple explanation on the operation and equation of phase motion of an injectionsynchronized oscillator in the presence of incoming noise in a simple way with particular reference to the effect of partly instantaneous limiting, due to the self-bias circuit of the oscillator. A simple relation between the mean-square frequency error and the time constant of the self-bias circuit has also been found by the application of the Fokker-Planck technique.

Self-steering array repeater

Abstract: A self-steering phased antenna array repeater system in which signals from a distant source at two spaced receptors are relatively shifted in phase and combined in a square law mixer. The output mixer current is a function of their phase difference and indicates the direction in which the signals arrive. This current is used to bring the phase of received signals together for combining and to introduce the same phase difference but of opposite sign for re-radiation by applying the current as the control for at least one injection locked oscillator which produces a phase shift according to the same function as the mixer output.

Injected signal characteristics of high-power avalanche diode oscillators

Abstract: Efficient injection locking results and other injected signal characteristics of high-power avalanche diode oscillators are presented. An injection locking figure of merit as high as 0.145 has been obtained.

The effect of operating parameters and oscillator characteristics upon the phase angle between a locked X-band Gunn oscillator and its locking signal

Abstract: Experiments have been carried out to measure the phase angle between a locked negative-resistance (Gunn) oscillator and its locking oscillator. Phase angle has been measured as a function of ambient temperature, oscillator bias voltage, locking power, and the voltage applied to a varactor tuning diode coupled into the locked oscillator. Results indicate that given a knowledge of the oscillator characteristics and the operating conditions, it is possible to predict, with reasonable accuracy, the phase of the locked oscillator. The relative merits of various methods of phase control are discussed and it is concluded that the best method is to use a varactor diode coupled into the negative-resistance oscillator.

On Injection-Locking Figure of Merit for Avalanche, Gunn, and Other Oscillators

Abstract: Injection-locking figure of merit has been derived for a negative-resistance oscillator in terms of the frequency compliance coefficient. A method of estimating this under small-injected-signal conditions for any device operating in any mode and a given circuit is described. The method requires the knowledge of the device impedance evaluated either from a large-signal analysis or experimentally and a proper description of the microwave circuit. A practical case of a Gunn-effect device operating in the quenched-domain mode has been described for illustration.

Criterion for Nonreciprocal Injection Locking of Bilateral Microwave Oscillators (Correspondence)

Abstract: A criterion is presented for establishing the required degree of isolation between injection-locked microwave oscillators to prevent reverse Iocking. In particular, the effect of circulator directivity and oscillator harmonics on the performance of the locking circuit is discussed. The injection-locked performance of pulsed and CW transferred electron oscillators is used as an example.

Locked oscillator circuits

Abstract: One embodiment of a microwave FM demodulator comprises first and second branches to which the input FM signal is applied. The signal on the first branch controls the output phase of an injection-locked oscillator. The output of the oscillator and the signal on the second branch are combined by a hybrid coupler and applied to a balanced phase-sensitive detector comprising first and second oppositely-poled diodes connected to opposite sides of an output resistance. A center tap on the output resistor derives a voltage having an amplitude proportional to the input signal frequency. In another embodiment, the locked oscillator is connected to a reflection-type transmission line with transmission line probes used for deriving inputs to the balanced detector. In other embodiments, the output voltage is used to make the locked oscillator center frequency track the input locking frequency.

Design of multiple-input phase-locked oscillator in mutually synchronised system

Abstract: The multiple-input phase-locked oscillator used as the clock source of each office in mutually synchronised systems should be designed to obtain a compromise between several conflicting requirements. The stability of the system is needed, although the phase difference between offices should be small, and fast responses to large changes in system parameters are needed, although jitter reduction is required. The letter gives the optimum design parameter to provide a compromise between these requirements. Two schemes for a stabilised variable-frequency oscillator are proposed, together with the results of an experiment which obtained an overall stability of 0.5×10?7.