Abstract: The oscillation frequency of a variable frequency oscillator is swept by a sweep signal from a sweep signal generator and the oscillation frequency is compared with a preset sweep start frequency for detecting coincidence therebetween. Upon detecting the coincidence, the sweep operation of the sweep signal generator is stopped and, at the same time, the oscillation frequency of the variable frequency oscillator is made by phase lock loop means to be phase-synchronized with a reference frequency. When the phase synchronization is established, an error signal in the phase synchronization is held and the loop of the phase lock loop means is cut off and then the error signal is applied to the sweep signal generator to re-start the frequency sweep of the variable freqency oscillator. When coincidence is detected between the oscillation frequency of the variable frequency oscillator and a preset sweep stop frequency, the sweep operation is stopped.

Abstract: A sweep control circuit and method for maintaining a constant swept frequency range of a voltage-controlled oscillator when switching between linear and non-linear sweeping functions is provided. The sweep control circuit includes a linear amplifier and an antilogarithmic amplifier, each of which has an output voltage window that is matched to the linear dynamic range of the CVO. Independently selected start and stop voltages are adjustable over the entire linear range of the VCO to set the lower and upper frequency limits as desired for either a linear or a logarithmic sweep. Log converters are utilized to map the linear start and stop voltages to logarithmic counterparts so that the VCO frequency does not shift when switching from one function to the other. This permits a single start frequency control and a single stop frequency control to be employed. A ramp voltage, which is appropriately scaled for both the linear and logarithmic functions, is applied to sweep the VCO.

Abstract: In a swept frequency oscillator arrangement compensation is provided for the non-linearities in the tuning sensitivity of the oscillator. The non-linearities are initially measured and stored. Subsequently the stored values are used to control the rate at which the clock pulses are integrated to produce a control signal for the oscillator.

Abstract: A broadband high frequency signal generator is disclosed having a low and a high frequency swept signal source connected to a YIG tuned frequency multiplier. One end of an output coupling loop for the YIG is connected to ground through a PIN diode, and the low frequency signal source is connected to the junction of the output coupling loop and the PIN diode. When the PIN diode is caused to conduct, signals from the high frequency source are passed through the YIG tuned multiplier to an output in the conventional manner. When the PIN diode is not conducting, signals from the low frequency source are passed to the output through the output coupling loop.

Abstract: The sweep rate of a linearly swept frequency generator is increased while maintaining strict linearity by artificially increasing the number of zero axis crossings of the output signal from a linearly swept voltage controlled oscillator over those that would naturally occur during a linear sweep. This permits an increased sampling rate which, in turn, permits the oscillator sweep rate to be increased without loss of accuracy. Increasing the number of zero axis crossings is accomplished by introducing phase shifts in the output of the oscillator at calculated sampling times with phase shifting being accomplished indirectly by heterodyning the swept oscillator output with the output from a fixed oscillator whose output signal is phase shifted by discrete amounts during the frequency sweep. Only a small number of phase shifts need be introduced due to the discovery of certain symmetries of phase when sweeping through a frequency range.

Abstract: A sweep signal generation system for producing an output sweep signal of very high frequency includes a circuit for generating an input sweep signal, and a phase locked loop which includes a phase detector, a voltage controlled oscillator and a harmonic frequency mixer. The output sweep signal is applied to the harmonic mixer together with a local oscillator signal of fixed frequency, the output from the harmonic frequency mixer being applied to the phase detector together with the input sweep signal. The output from the phase detector is applied to the voltage controlled oscillator to cause the frequency of the output thereof to be swept in accordance with variation of the input sweep signal.

Abstract: A resonant cavity of a microwave generator, such as a magnetron oscillator, is provided with a tuning piston which is rectilinearly displaceable between two terminal positions, corresponding to respective limiting frequencies, by means of a rotating crankshaft whose eccentric portion constitutes the inner race of a ball or roller bearing. The outer race of that bearing rolls, directly or through the intermediary of a captive spherical or cylindrical coupling member, on a transverse face of the tuning piston held in contact therewith by spring pressure.

Abstract: A co-axial magnetron in which the microwave output frequency can be rapidly altered within a particular frequency band. A movable tuning plate is coupled to a mechanical tuning fork which is set into vibration by an alternating voltage applied to a solenoid.

Abstract: A resonant cavity of a microwave generator, such as a magnetron oscillator, is provided with a tuning piston which is displaceable between two terminal positions, corresponding to respective limiting frequencies, by means of a rotating crank-shaft whose eccentric portion is hugged by a nonrotatable follower ring suspended between two flexible wires or blades extending generally radially outward from diametrically opposite points of the ring. A yoke spacedly surrounding the ring is provided with two oppositely extending tubular arms in which the wires or blades are received with clearance while being fastened to the ends of these arms remote from the yoke; the tuning piston is rigidly connected with one of the two arms.

Abstract: A method is presented for generating highly-linear periodic frequency sweeps by providing closed-loop linearity corrections for linear frequency sweeps that are error averaged over a number of sweeps. The technique can operate with a variable sweep period.

Abstract: A resonant cavity of a microwave generator, such as a magnetron oscillator, is provided with a tuning piston which is displaceable between two terminal positions, corresponding to respective limiting frequencies f.sub.1 and f.sub.2, by means of a rotating crankshaft to which the piston is coupled by a linkage including a pitman with a substantially linearly guided extremity remote from the crankshaft axis. The length p of the pitman, measured between the pivotal axes of its extremities, is related to the eccentricity e of the crankshaft by the expression ##EQU1## where q is the length of the stroke of the linearly guided extremity between its extended dead-center position and an intermediate position in which the operating frequency of the generator has its mean value (f.sub.1 +f.sub.2)/2. With this dimensioning, the frequency varies as a sinusoidal function of the crankshaft angle and is therefore proportional to the output voltage of an angle sensor coupled with the crankshaft.

Abstract: A voltage-controlled type oscillator utilizing charging and discharging of a capacitor. The oscillation frequency is made to vary in exact proportion to the control voltage by variably controlling electric charge in accordance with the control voltage during charging and discharging of the capacitor.

Abstract: A sampling linearizer including a phase shifter for use in improving the accuracy of an FM generated waveform with respect to a desired frequency rate of change is disclosed. The sampling linearizer comprises an oscillator for generating a reference frequency signal; a mixer governed by the generated FM waveform signal and the reference frequency signal to generate a first signal which is sampled at predetermined sampling times; and a linearizing servo controller which is governed by the sampled signal to reduce the inaccuracies in the genereated FM waveform with respect to the desired frequency rate of change. The sampling linearizer further includes a phase shifter disposed between the oscillator and mixer thereof and operative upon the reference frequency signal to generate another signal, the phase shifter being operative to shift the phase of the another signal with respect to the reference frequency signal as governed by a sequence of control signals representative of predetermined phase shift values.

Abstract: A variable frequency oscillator is disclosed which is electronically and periodically swept from one frequency to another. Prior to the beginning of each sweep, the variable frequency oscillator is phase locked to a reference signal source and the error voltage in the phase lock loop is stored. When the sweep begins the phase lock loop is opened and the error voltage is summed with a sweep voltage to provide for correction of oscillator drift on a sweep by sweep basis.

Abstract: A method of linearizing a voltage controlled oscillator wherein a control signal is shaped into ramp form by a memory and transmitted to the control input terminal of a voltage controlled oscillator to be linearized thereby causing the oscillator to generate a chirp. Nonlinearities in the chirp are detected and the memory reprogrammed so as to diminish detected nonlinearities by reshaping the ramp control signal.

Abstract: A variable frequency oscillator including a nonlinear element for varying the frequency has alternately attached thereto a phase lock loop for maintaining the base or starting frequency of the oscillator substantially constant, and a sweep generator with a rate error loop for sensing the frequency linearity of the output sweep and altering the input signal to maintain the output linear.

Abstract: A combination electronic device provides a digital sweep circuit adapted to generate a sweep signal which increases in frequency at constant intervals over a selected range of frequencies and over a selected period of time.

Abstract: A device for generating a repetitive, highly-linear, frequency ramp. A voltage controlled oscillator responds to a ramp generator to produce the desired frequency modulation, and means are included for modifying the ramp amplitude vs. time shape as a function of the variation of instantaneous values of the frequency ramp from the linearized ideal.

Abstract: A voltage controlled sweep oscillator system which is stepped in frequency, avoiding transitional frequencies. Only discrete frequencies are provided by dividing the system into two segments wherein each segment comprises a voltage-controlled oscillator (VCO) in a phase-locked loop. A multiplexer provides one VCO signal to the output while the other VCO is stepping its frequency, and vice versa. Frequency control in each segment is achieved by comparing the divided output of a VCO with a reference frequency signal and making adjustments to cancel any errors that may appear.

Abstract: A method and apparatus for controlling rodents is disclosed utilizing ultrasonic signals. The ultrasonic signals are of the square wave type. They are varied from approximately 28 to 20 KHz during the first time period of approximately 20 microseconds, then maintained at a frequency of approximately 20 KHz for a second time period of approximately 780 microseconds. The generated square wave signals are converted to sound waves by a transducer such as a speaker. The frequencies employed and the duration of these frequencies are selected to maximize the irritating effect upon the rodents.

Abstract: A sweep output generator in which an a-c voltage of small amplitude is superimposed upon a sweep voltage applied to a variable reactance element of a local sweep voltage controlled oscillator for sweeping the local oscillator frequency and also for frequency modulation. The frequency modulated local sweep oscillator output and the output of a second voltage controlled oscillator are coupled to a mixer to obtain an intermediate frequency signal. The intermediate frequency signal is frequency demodulated through a frequency discriminator, whose output is in turn integrated to obtain a sweep output voltage of a characteristic similar to the normalized oscillation frequency versus impressed voltage characteristic of the local oscillator.

Abstract: A system for automatically maintaining the center frequency of a swept voltage controlled oscillator. At a known amplitude of sweep voltage input, a lock pulse is actuated. The oscillator output is divided by a number N and applied simultaneously with the reference signal to a phase and/or frequency detector. The detected signal is applied via a gate under the control of such lock pulse to a memorization unit whose output is used to maintain the center frequency.

Abstract: An arrangement for simultaneously producing signals having a decreasing frequency and signals having an increasing frequency. In this arrangement the signals have frequencies which are complementary relative to the double value of a central frequency. The arrangement includes a pair of voltage-controlled oscillators controlled by signals supplied by a control generator. The arrangement is characterized in that for each oscillator there is provided with a phase control loop and that the control generator is of the digital type designed to supply two pairs of digital signals. One pair is applied to the frequency dividers and the other is applied to the oscillators so as to tune them to such a frequency that they are in the operating range of the phase control loop.Use: Radio-electric transmission of data.

Abstract: Linear accuracy of the output-signal frequency of a scanning oscillator is aintained through monitoring the location in a shift register of a pulse whose position is indicative of the frequency error from a desired scanning oscillator output-signal frequency.