Abstract: A voltage controlled oscillator circuit with a high power supply rejection ratio incorporates a clamping transistor with respect to each output terminal which limits the signal swing of the output terminal. The limited voltage swing allows relatively large movements in the power supply and ground voltages without causing significant changes in the frequency of the output signals. Such an oscillator circuit may be incorporated into an integrated circuit characterized by noisy power supply and ground conductors. Additionally, multiple delayed versions of the output frequency may be created using a level shifter circuit and a buffer circuit. The oscillator circuit is relatively quick to react to changes in the controlling voltage, adjusting the oscillation frequency in a relatively short time interval.

Abstract: A voltage controlled oscillator that completely eliminates the need for any externally mounted coil and capacitor includes a first loop and a second loop. The first loop provides band-limiting of an output signal of an amplifier through a bandpass filter to provide oscillation at a frequency of a resonant point of the bandpass filter, and the second loop controls the oscillation amplitude, so that a lowpass filter output with a 90.degree. phase is extracted from the first loop, while a bandpass filter output with a 0.degree. phase is extracted from the second loop. The voltage controlled oscillator may be used in an automatic fine tuning circuit for television.

Abstract: A circuit for causing an element to produce a substantially linear response to an input signal comprising an element for providing a response, a transistor oscillator circuit for providing an electrical output signal of variable amplitude to excite the element in response to the input signal, the transistor oscillator circuit normally causing the electrical output signal to vary non-linearly with respect to the input signal, and microprocessor means for correcting the non-linear relationship between the input signal and the electrical output signal to thereby cause the electrical output signal to vary substantially linearly with respect to the input signal when the input signal is applied to the microprocessor means.

Abstract: The disclosure is directed to a Lever oscillator for use in high resistance resonator applications, especially for use with quartz resonator sensors. The oscillator is designed to operate over a wide dynamic range of resonator resistance due to damping of the resonator in mediums such as liquids. An oscillator design is presented that allows both frequency and loss (R.sub.m) of the resonator to be determined over a wide dynamic range of resonator loss. The Lever oscillator uses negative feedback in a differential amplifier configuration to actively and variably divide (or leverage) the resonator impedance such that the oscillator can maintain the phase and gain of the loop over a wide range of resonator resistance.

Abstract: An electrical circuit comprising means for receiving an input signal for encoding or modulating and amplification. Multiple amplification stages including at least one transconductance amplifier are provided. There are means for having the input signal modulate the oscillator constituted by the multiple amplification stages to provide a 360.degree. phase-shifted signal at a predetermined frequency. Gain control means are also provided for developing level for permitting oscillation under conditions including at least the conditions of turn on of the circuit and other operating conditions. The gain control means includes a transistor and resistor network for adjusting the gain to sustain the oscillation. The transistor and resistor also regulate amplification of an intermediate stage of the amplifier. The preamplifier directly converts an EKG and/or other signals to linearized control currents which modulate the oscillator.

Abstract: A switching boosting circuit including a clock oscillating circuit having a Schmitt trigger inverter, a boosted-voltage inducing circuit which is actuated in a switching-operation mode in response to the output clock of the clock oscillating circuit to induce a boosted voltage, a capacitor which is charged by the boosted voltage from the boosted-voltage inducing circuit to store energy to be supplied to a load, and a feedback path for feeding back current whose intensity corresponds to the load from the capacitor to the clock oscillating circuit. The feedback current acts such that the duty ratio of the switching operation is set to be smaller than a predetermined reference duty ratio, and the feedback path includes a Zener diode for reducing the boosted voltage below a predetermined value.

Abstract: A self-regulating oscillator circuit and method are disclosed. Specifically, a method is described whereby an oscillator having an active device is operated. The oscillator is operated by providing a current through the active device, as well as through a reference device connected in series with the active device of the oscillator. A reference voltage across the reference device is sampled, and a regulated voltage is generated by adding a predetermined voltage to the sampled reference voltage. Finally, the regulated voltage is applied to the active device of the oscillator. In one circuit embodiment, the oscillator as described includes a gallium arsenide FET structure which cooperates with a resonant structure to produce a reflection-type oscillator. In addition, a regulator circuit is described including an isolating op amp which samples the reference voltage from the active device of the oscillator and provides its output to a voltage source device.

Abstract: A tuneable crystal oscillator arrangement includes a piezo-electric, e.g. quartz, crystal and drive current means therefor. A reactance is arranged in series with the crystal and is fed with a current corresponding to the crystal drive current. The corresponding voltage developed across the impedance is fed via a variable gain amplifier back to the crystal. The reactance comprises a number of impedances, there being current steering means for dividing the current between the impedances. This determines the effective value of the reactance and provides a control or adjustment of the crystal frequency.

Abstract: A low-power crystal oscillator circuit is disclosed that includes an amplifier section having a switchable compensation network. In one embodiment, the oscillator circuit incorporates inverter amplifiers to generate a square-wave output signal that can be used, for example, as a clock signal to drive microprocessors and other digital circuitry. The invention takes advantage of the observation that, if the uncompensated bandwidth is not too excessive, compensation is only needed at start-up to ensure oscillation at the desired crystal frequency. Once the desired oscillation is attained, most of the oscillation cycle occurs during the non-linear regions of the amplifier. These non-linear regions are characterized by low gain, thus suppressing any spurious oscillation. The compensation network is removed after start-up to reduce power consumption.

Abstract: A variable reluctance transducer system incorporating digital control of parallel resonant circuits including two inductive sensors L1 and L2 on each side of a flat diaphram. The dual variable reluctance elements provide dual frequency signals for digital calculation to obtain a quotient of the frequencies, thereby substantially eliminating the resonant frequencies as a variable in the accuracy of the device. Manipulation of the produced quotient by a micro-controller 10 employing digital calibration tables stored in a programmable read only memory 14 allows calibration reponsive to a temperature sensor 16, thereby substantially eliminating temperature induced errors in the system, further increasing accuracy.

Abstract: A microwave synthesiser comprising: a plurality of oscillator sources (1, 13, 3, 15, 5, 17, 7), each for generating signals over a range of frequencies, said ranges of frequencies together extending over a total range of frequencies generated; phase locked loops (19, 31, 83, 37, 38, 41, 81) for phase-locking any selected one of said oscillator sources (1, 13, 3, 15, 5, 17, 7) so that it generates signals of a frequency at which it is set; a single low harmonic modulator (21) for modulating the signals generated by the selected one of said oscillator sources (1, 13, 3, 15, 5, 17, 7), the modulated signals passing to an output (27) of said synthesiser; and at said output (27) elements (25, 29) for detecting the power of the signals at said output (27), the modulation by said single low harmonic modulator (21) being controlled in dependence on the detected power thereby to control the power of the signals at said output (27).

Abstract: The present invention comprises an oscillator including a transformer having a first winding with a power feed to the center tap. A first pair of transistors in a push-pull configuration are connected at the emitter electrodes across the second winding of the transformer. A center tap on the second winding is provided for a negative polarity power return. The base electrodes of the transistors are commonly connected to receive a control current and the collector electrodes of the transistors are connected across a first winding of the transformer. A capacitive element is connected across the first winding to create a tuned circuit within an oscillator.

Abstract: The output of the first CMOS inverter, connected as an oscillator, is applied to the inputs of second and third CMOS inverters that have logic threshold voltages higher and lower than the logic threshold voltage of the first inverter. The outputs of the second and third CMOS inverters are connected to an output circuit via a logic output circuit. The output of the logic output circuit is shorted by an output control circuit, under the control of the outputs of the second and third CMOS inverters, when the output of the oscillator is between the logic threshold voltages of the second and third inverters.

Abstract: Crystal oscillator and method which in one embodiment have a crystal element connected in a positive feedback loop with a charge amplifier and an integrator, with the gain of the loop being maintained at a level of unity. Compensation is provided to offset the effects of shunt capacitance in the crystal element, and precise phase control is maintained around the loop. In other embodiments, a crystal element is connected in a series feedback loop with a buffer amplifier, and operation is provided by maintaining the oscillation signal at level at which distortion, clipping, and saturation do not occur. Compensation for shunt capacitance across the crystal element is provided by applying a compensation signal which is equal in amplitude but opposite in phase to the signal passing through the shunt capacitance to the input terminal of the buffer amplifier to cancel the effect of the shunt capacitance.

Abstract: An actively biased oscillator (200) includes a set of current sensing components (214,216) for sensing the amount of current flowing into the first terminal of the amplifier; and a differential amplifier (212) responsive to the current sensing components for automatically adjusting the amount of current flowing into the second terminal of the amplifier.

Abstract: A resonant circuit comprises first and second amplifiers. An input of the second amplifier is coupled to an output of the first amplifier, and an output of the second amplifier is cross-coupled to an input of the first amplifier. The first amplifier has a first gain and a 90 degree phase shift between its input and its output at a resonant frequency of the resonant circuit. The second amplifier has a second gain and a 90 degree phase shift between its input and its output at the resonant frequency of the resonant circuit. The second gain is different from the first gain. The resonant circuit can have a first port and second ports coupled to an input and an output respectively of one of the first and second amplifiers. Because the gains of the first and second amplifiers differ, the gain from the first port to the second port of the resonant circuit will differ from the gain from the second port to the first port.

Abstract: On an integrated circuit, a power limiting circuit is added to a crystal oscillator for limiting power dissipation in the crystal to a prescribed safe power dissipation range. The power limiting circuit includes a Pierce design crystal-controlled oscillator coupled to a self-stabilizing circuit. The self-stabilizing circuit detects the oscillation amplitudes of the crystal controlled oscillator. The self-stabilizing circuit prevents the oscillations from exceeding a predetermined maximum power dissipation level for the crystal. The self-stabilizing circuit includes a means for detecting oscillation amplitudes and means for limiting the gain of the crystal controlled oscillator circuit. Therefore, independent of manufacturing tolerances from integrated circuit to integrated circuit, the self-stabilizing circuit assures that the maximum power dissipation level of the crystal is not exceeded.

Abstract: A voltage controlled oscillator circuit including an oscillator circuit having first and second terminals to which an external inductance is connected. A frequency control voltage (V.sub.F) is applied through a bias circuit to the second terminal for varying the center frequency. The oscillator circuit may have an AGC circuit or a modulation circuit connected to it. An output amplifier is connected with the first terminal and has an adjustable output impedance for matching the input impedance of a load circuit.

Abstract: Voltage controlled oscillator provided with a resonant network, an amplifier and a reactive network, all incorporated in an oscillator loop, the reactive network having one or more reactive components whose values depend on a control signal fed to a control input, so that the oscillator frequency can be regulated with said control signal. A control loop is provided between the resonant network and the reactive network, with which control loop the difference is determined between a measure of the imaginary part of the impedance or admittance of the resonant network and the control signal acting as reference quantity. The imaginary part of the impedance or admittance of the reactive network is regulated with said difference. The control loop contains a derivation circuit for deriving said measure and a differential amplifier, to one input of which the output signal of the derivation circuit is fed and to the other input of which the control signal is fed.

Abstract: A crystal oscillator uses automatic gain control to minimize the operating current through its inverting amplifier. The power supply potential to switching transistors of the amplifier is reduced by the automatic gain control to a level substantially equal to the sum of the switching thresholds thereof which minimizes simultaneous conduction through the switching transistors and associated operating current. The low level output signal of the amplifier becomes sinusoidal about a DC bias point operating at the resonant frequency of the crystal which eliminates undesirable harmonicas interfering with the crystal's natural vibration. The sinusoidal output signal may be buffered and level-shifted to a useable state.

Abstract: Controllable oscillator circuit comprising a regenerative loop which incorporates a cascade circuit of first and second sections each having a controllable gain and a phase shift which is 90.degree. at the oscillation frequency, and an amplitude detection arrangement which is coupled between an output and a control input of at least one of the two sections.

Abstract: The invention provides an arrangement for reducing waveform errors such as errors in phase or amplitude in output pulses produced by pulsed power output devices such as klystrons by generating an error voltage representing the extent of error still present in the trailing edge of the previous output pulse, using the error voltage to provide a stored control voltage, and applying the stored control voltage to the pulsed power output device to limit the extent of error in the leading edge of the next output pulse.

Abstract: A series-feedback crystal oscillator has a crystal element in series with a buffer amplifier. The oscillator maintains a linear oscillation signal by using an amplitude control circuit to hold the oscillation signal to a certain level at which distortion, clipping, or saturation does not occur. A control signal indicative of the amplitude of the oscillation signal linearly multiplies the oscillation signal to control the amplitude of the oscillation signal. Shunt capacitance across the crystal is compensated for by connecting a compensating capacitor to the same input terminal of the buffer amplifier as is connected the crystal. A compensating signal, which is equal in amplitude but opposite in phase to the signal passing through the shunt capacitance of the crystal is fed to the input terminal of the buffer amplifier to cancel the effect of the shunt capacitance. A noninverted tracer signal is injected in the feedback loop and passes through the shunt capacitance.

Abstract: Disclosed is an oscillator circuit comprised of a sharp bandpass filter having an input and an output; a linear gain stage having an input and an output, the output of the sharp bandpass filter being connected to the input of the linear stage; a limiter having an input and an output, the output of the linear stage being connected to the input of the limiter; and a feedback loop having an input and an output, the output of the limiter being connected to the input of the feedback loop and the output of the feedback loop being connected to the input of the sharp bandpass filter, wherein the improvement being comprised of the limiter being a symmetrical active clamp.

Abstract: An integratable amplitude-regulated oscillator circuit includes a resonator element, a control element having a control input, an inverter having an output and an input coupled to one another through the resonator element and having a quadrature-axis current component being variable by the control element, an amplitude regulating circuit having an input connected to the input of the inverter and an output connected to the control input of the control element, and an output stage having an input connected to the input of the inverter. The amplitude regulating circuit includes a differential amplifier having an inverting input and a non-inverting input, a first peak value rectifier connected upstream of the inverting input, and a second peak value rectifier connected upstream of the non-inverting input.

Abstract: An oscillator circuit for supplying a gas discharge path. A self-oscillating oscillator is controlled by pulses whose width, amplitude, and/or frequency are regulated as necessary to stabilize the oscillator output power, energy, and/or voltage.

Abstract: A high-frequency power oscillator includes a tetrode electron tube (5), a current source (3) and a voltage-limiting circuit (4). The current source (3) is connected to the screen grid of the tetrode (5). This limits the screen grid current when the voltage on the anode of the tetrode (5) is momentarily lower than the screen grid voltage. Between the screen grid and the cathode of the tetrode the voltage-limiting circuit (4) is inserted. This circuit starts to conduct above a predetermined threshold value. This forms a limit to the screen grid voltage so that is is possible to operate the tetrode (5) in a pulsating manner. The voltage-limiting circuit may comprise a triode (4) with a voltage source (2) providing a constant voltage between the grid and the cathode of the triode (4).

Abstract: A heterodyne stage of a receiver which includes a conventional mixer circuit and local oscillator circuit further includes a differential amplifier circuit which measures the amplitude of the injection signal generated by the local oscillator circuit and controls it precisely to a desired reference level by adjusting the current bias supply to the local oscillator circuit within a banded range to ensure start-up of the local oscillator upon energization and to protect against loss of injection signal under all operating conditions. The differential amplifier circuit provides for a precise amplitude reference setting and sufficient closed-loop gain for controlling the amplitude of the injection signal with a minimum of error between the measured and reference values.

Abstract: An amplitude stabilized oscillator which includes an amplifier having an input, an output, and a control terminal. The amplifier has a frequency determining feedback circuit connected between its output and input terminals, and has a control voltage produced by two opposite current sources applied to its control terminal. An amplitude detector detects the oscillator output amplitude during at most one half of each oscillation period and produces an amplitude stabilizing signal which is applied to one of the two current sources.

Abstract: A power amplifier driven in the switching mode is started into oscillation by a pulse from an auxiliary oscillator when it is first activated. Reactive currents thereby resulting in an output filter network, containing a series resonant circuit followed by a parallel resonant circuit which is connected across a load impedance, then produce the switching in of a feedback circuit, after which the amplifier oscillates in a self-excited mode, at a frequency determined by the tuning of the resonant circuits.

Abstract: An ultrasonic generator, particularly for use in ultrasonic cleaning systems, provides a constant ultrasonic power output for a cleaning tank or chamber. A generator output stage fed from an unsmoothed mains power supply receives signals from an oscillator via a pulse-width modulation circuit. A power control feedback loop monitors the mains current, or alternatively the output signal from the output stage, and provides a compensation signal to the pulse-width modulation circuit. A frequency control feedback loop senses the current in the output from the output stage and tunes the generator for maximum current in this output.

Abstract: A monolithically integrable amplitude-controllable oscillator amplifier circuit includes a differential amplifier. The bases of first, second and third transistors are acted upon by a direct voltage. A first capacitor connects the base of the second transistor to a reference potential. A frequency-determining circuit element is connected to the base of a first transistor, the collector of the second transistor and the oscillator amplifier. The collector of the first transistor is connected directly to the emitter of the third transistor forming a cascode circuit. The collector of the third transistor is connected to a first potential. The collector of the second transistor forms an amplifier output. A first resistor is connected between the collector of the second transistor and a second potential.

Abstract: A signal source for generating a well-controlled, predictable oscillating output signal within a short, predetermined and constant start-up time is disclosed. The invention includes a switchable current source for selectively providing an electrical signal to a tank circuit which, in response, provides an oscillating output signal. A control circuit, comprising a comparator is connected to the tank circuit for providing a control signal to the switchable current source which causes the current source to switch in response to the output signal. Particular embodiments of the invention include means for controlling the amplitude of the oscillating output signal, means for controlling the transconductance of the current source, and means for starting the signal source.

Abstract: A high-frequency generator having automatic power-control for use in high-frequency surgery. The frequency of a high-frequency generator is adjustable by electronic circuit brought by a control circuit to a value such that at the output of the power amplifier there is an optimal phase relation between output voltage and output current, i.e., generally a phase shift of zero. The signal necessary for the control of the output power is obtained from harmonic oscillations generated by the arc at the surgical probe. A harmonic-measuring device to obtain the harmonic oscillations generated by the arc at the surgical probe has a phase-controlled rectifier which is controlled by the oscillator of the high-frequency generator. A simple filter is used at the output of the power amplifier, and the measurement filter used before the harmonic-measuring device can either be completely eliminated or need only be very simple in construction.

Abstract: An oscillator circuit which includes a differential amplifier in combination with a negative feedback network and a positive feedback network connected to the amplifier. One of these networks determines the frequency of the generated oscillation. In order to obtain an oscillation of constant amplitude, the negative feedback network comprises a current limiter active as a controllable one-port network which is connected between the negative feedback input of the differential amplifier and a fixed potential.

Abstract: A DC voltage is synthesized from a combination of a plurality of N phases of an oscillator signal. A diode circuit is used to combine the N phases, and a relationship between components of the circuit is established to eliminate the Nth harmonic of the oscillator signal from the synthesized DC voltage. Provision of non-zero input series resistances for four diodes together with a non-zero summing output resistance therefor provides a DC voltage having no harmonics below the eighth harmonic for a double-integrating oscillator providing four equally displaced phases of a signal.

Abstract: A voltage controlled oscillator circuit of a type having a tank circuit for generating oscillations which includes a means for establishing a fixed bias voltage with respect to ground at a bias end of said tank circuit, means for drawing current from an a.c. end of said tank so as to control the tank gain, and an AGC capacitor. A constant current source is coupled to the AGC capacitor for supplying it with a constant charging current. Means are provided for discharging the AGC capacitor at a voltage level determined by a ratio of resistors and a transistor emitter-base ratio.

Abstract: Changes in the ultrasonic properties of fiber-reinforced plastics during the curing process are monitored by a marginal oscillator to determine the degree of cure. The plastic sample and transmitting and receiving transducers serve as a narrowband acoustic resonator and are placed in the feedback loop of a variable gain amplifier; using gain control the system is allowed to marginally oscillate. The resonant frequency of the sample and amplifier gain are related to the velocity and attenuation of sound in the plastic and are determined by measuring the received signal frequency and amplifier gain control voltage. The system has frequency locking means to track changes in resonant frequency during the cure cycle.

Abstract: Light to be measured is input to a diffraction grating after is has been oscillated by a wavelength modulation device with a constant frequency F. The light is incident to the diffraction grating at an angle of incidence, .theta., and is oscillated with a frequency F with a center angle of incidence, .theta..sub.0, as a center. An output spectrum of said diffraction grating is received by a photoelectric converter. An electric signal from the photoelectric converter is oscillated with a frequency F over a wavelength range of .lambda..sub.0 .+-..DELTA..lambda. where .lambda..sub.0 is a center wavelength measured at the center angle of incidence .theta..sub.0. The oscillated spectrum signal is synchronously detected, by a synchronous detector, with a frequency 2F through a high-pass filter, obtaining a variation spectrum at the measured center wavelength .lambda..sub.0.

Abstract: A processor-controlled drive motor system for tuning a cavity klystron monitors the output (amplitude-vs-frequency) of the klystron and compares that monitored performance output with an intended amplitude-vs-frequency profile. Differences between the two characteristics are employed by the processor to generate a set of tuning cavity control signals through which respective stepping motors for displacing each cavity tuning slug are driven. The processor iteratively adjusts the cavity tuner control signals in accordance with a prescribed kylstron tuning program until the monitored amplitude response is within a prescribed tolerance of a preestablished characteristic stored in memory.

Abstract: An oscillator circuit in a semiconductor substrate of an integrated circuit, includes a gain correction circuit portion connected between the output terminal of the feedback circuit portion and the input end of the amplifier circuit portion composed of MOS transistors. The gain correction circuit portion suppresses the excessive amplitude of the output signal of the feedback circuit portion, so that the characteristic of the waveform of the output signal of the oscillator device is improved.

Abstract: A method and means for reducing noise in a GaAs FET oscillator circuit is described. The circuit of the present invention achieves low noise oscillator operation by driving the gate input of the GaAs FET oscillator circuit with a source of voltage which exhibits a low impedance at baseband frequencies and driving the drain input with a source of current which exhibits a high impedance at said frequencies. The present invention further operates to control the D.C. voltage present on the drain terminal of the GaAs FET device regardless of the drain current, while simultaneously maintaining a constant D.C. drain current at some predetermined value which corresponds to optimum low-noise operation.

Abstract: An electric oscillator comprising a resonant circuit wherein, after switching on the oscillator, it takes a short time to build up to a desired amplitude of oscillation. To reduce the oscillation build-up time of the oscillator, a current supply source is provided along with control elements and switching means for changing the operating mode of the oscillator from a standby mode to an oscillatory mode, and vice versa. During the standby mode a charging current is supplied to the coil of the resonant circuit so that when switching over into the oscillatory mode, the charging current to the coil is interrupted. As a result, the control elements are immediately supplied with oscillations of the desired oscillatory amplitude.

Abstract: Disclosed is a proximity switch which includes an oscillation circuit whose oscillation output is variable depending on the inductance of a coil so that an object in proximity may be detected from the decline in the oscillation output. Further, the oscillation gain of this oscillation circuit is variable according to an input from an external source. Thus, for the purpose of increasing the recovery speed of the oscillation which has dropped as a result of detecting an approaching object, comparison circuits are provided so that upon reduction in the oscillation output of the oscillation circuit a certain signal is applied to the oscillation circuit to increase its oscillation gain. As a result, even when an object in proximity is detected and the oscillation level is maintained at a certain low level so that the oscillation may be resumed quickly when the object has moved away from the proximity switch.

Abstract: A voltage controlled oscillator is disclosed wherein a peak detector is used to control the gain of the active device within the oscillator in response to a control signal taken from the resonant circuit. The control signal is a RF potential developed across a voltage divider within the resonant circuit. By controlling the gain of the active device from an RF voltage provided by a voltage divider, the RF output level of the oscillator "tracks" the DC bias level of the steering line. Therefore, varactor diodes rectification is prevented while contemporaniously allowing maximized output power.

Abstract: Oscillator circuit has a first and second transistors whose emitters are intercoupled and jointly connected to a variable current source, the first transistor being connected in a grounded-base connection. The oscillator current also has a parallel resonant circuit coupled to the collector of the first transistor, this collector being coupled for regenerative feedback of the circuit voltage to the base of the second transistor. Stabilization of the circuit voltage is accomplished by coupling the last-mentioned collector also to a control input of a variable current source, so that the collector current applied to the circuit is modulated in anti-phase with the circuit voltage, that is to say it instantaneously decreases at an increase of the circuit voltage and vice versa.

Abstract: A low noise oscillator is described suitable for use in an AM stereo radio receiver. The oscillator circuit includes means for controlling its amplitude at a constant low level. The oscillator is amenable to electronic tuning and IC construction.

Abstract: A circuit configuration is provided for reducing noise sidebands in the output of an oscillator due to modulation of the oscillation signal by characteristic noise produced by the amplifying element. A gallium arsenide field-effect transistor that produces characteristic noise is operated as a linear amplifier. Positive feedback to the input of the amplifier is provided by a resonator. The amplitude of the oscillation signal is limited by a distinct limiting circuit in the feedback loop, the input to which is isolated from the amplifier by a high pass filter, thereby divorcing the non-linear limiting function of the oscillator from the amplifying function where noise is generated.

Abstract: There is disclosed a drive regulation and control circuit for a tuning fork resonator also adaptable to other electrical devices wherein an approximately sine wave signal from a motion sensor is applied to an instantaneous level detector which causes a variable width pulse signal to be on during that portion of the sine wave signal where the instantaneous level exceeds an adjustable reference level; a control signal is generated with a magnitude varying as a moving average of the width of the variable width pulses; the control signal causes the reduction of current to the tuning fork drive to cause reduction of motion amplitude. An optional feature provides rapid response by activating a motion braking signal having a duration approximately equal to the variable width pulse "on" period.

Abstract: A high-frequency oscillator including an oscillation circuit (1) having a quartz crystal (X) and an amplifying element (Q.sub.2), a power amplifying circuit (3) for amplifying the output of the oscillation circuit, and a control system (Q.sub.7, 6) for varying a bias voltage of the amplifying element to thereby control the output power of the power amplification circuit. The control system comprises an FET (Q.sub.7) connected at the drain thereof to the amplifying element, and a control circuit (6) for applying a control signal to the gate of the FET.