Abstract: Monolithic integrated circuit oscillators, complementary metal oxide semiconductor (CMOS) voltage-controlled oscillators, integrated circuit oscillators, oscillator-forming methods, and oscillation methods are described. In one embodiment, a monolithic integrated circuit oscillator is provided and includes a semiconductive substrate. A field effect transistor is supported by the semiconductive substrate and an oscillator circuit is connected therewith. The oscillator circuit preferably comprises an inductor which is supported by the substrate and has an inductance value greater than or equal to about 4 nH. In another embodiment, a complementary metal oxide semiconductor (CMOS) voltage-controlled oscillator is provided and includes a metal oxide semiconductor field effect transistor (MOSFET) received by and supported over a silicon-containing substrate. The transistor has a gate, a source, and a drain.

Abstract: A radio frequency transmitter circuit including a user input switch for producing an input signal, an oscillator for producing a frequency signal having a first frequency, an antenna connected to the oscillator for broadcasting the frequency signal, a coupling circuit disposed a predetermined distance from the antenna, and a microprocessor for enabling the oscillator and activating the coupling circuit in response to the input signal. When the coupling circuit is activated, a reflected impedance, derived from a change in inductance, is reflected from the coupling circuit upon the antenna thereby shifting the frequency signal to a second frequency. Sequentially activating and deactivating the coupling circuit modulates the frequency signal.

Abstract: A voltage-controlled oscillator has a frequency of oscillation that is varied using a substrate on which the same circuit pattern as that of the voltage-controlled oscillator is printed. In a resonant circuit included in the voltage-controlled oscillator, a first land is arranged substantially parallel to an inductor. A second land is arranged substantially parallel to the inductor and to a variable-capacitance diode. The capacitances of capacitors attached to the first land and second land are changed in order to vary the frequency of oscillation of the voltage-controlled oscillator. The frequency of oscillation can be varied without the necessity of scraping the inductor through which a major signal passes. Therefore, electrical characteristics of the voltage-controlled oscillator are not degraded and the frequency of oscillation is very steady. The frequency of oscillation can be varied merely by changing the capacitances of the capacitors attached to the first and second lands.

Abstract: Monolithic integrated circuit oscillators, complementary metal oxide semiconductor (CMOS) voltage-controlled oscillators, integrated circuit oscillators, oscillator-forming methods, and oscillation methods are described. In one embodiment, a monolithic integrated circuit oscillator is provided and includes a semiconductive substrate. A field effect transistor is supported by the semiconductive substrate and an oscillator circuit is connected therewith. The oscillator circuit preferably comprises an inductor which is supported by the substrate and has an inductance value greater than or equal to about 4 nH. In another embodiment, a complementary metal oxide semiconductor (CMOS) voltage-controlled oscillator is provided and includes a metal oxide semiconductor field effect transistor (MOSFET) received by and supported over a silicon-containing substrate. The transistor has a gate, a source, and a drain.

Abstract: A tuning signal is injected into an LC tank circuit oscillator, e.g., through an impedance (either reactive, inductive, capacitive and/or resistive) to tune the phase and/or frequency of the LC tank circuit oscillator. A negative resistance is included in parallel with the LC tank circuit oscillator to compensate for losses in the LC tank circuit, and a bias signal is provided to power the operation of the LC tank circuit. The tuning signal may be, e.g., an AC signal or a data signal. The tuning signal is injected into the LC tank circuit using capacitors, resistors, FET or bipolar transistors, and/or inductors. Multiple LC tank circuit oscillators may be used to provide stable multiplied or divided frequencies. In this case, the output of one LC tank circuit oscillator may be used to tune another LC tank circuit oscillator.

Abstract: A method and apparatus are provided for switching in metal insulator metal (MIM) capacitors and field effect transistor (FET) tuning capacitors for oscillator circuits. Apparatus for switching in metal-insulator-metal (MIM) capacitors and field effect transistor (FET) tuning capacitors for oscillator circuits includes a first differential oscillator node and a second differential oscillator node. A plurality of metal-insulator-metal (MIM) capacitors are connected to the first differential oscillator nodes and a plurality of metal-insulator-metal (MIM) capacitors are connected to the second differential oscillator nodes. A respective switching transistor is connected in series with an associated one of the metal-insulator-metal (MIM) capacitors. Each switching transistor receives a decoding input and is arranged for providing an open or a ground connection for the associated one of the metal-insulator-metal (MIM) capacitors.

Abstract: A high-Q precision integrated reversibly trimmable singleband oscillator and tunable multiband oscillator are presented that overcome the problems laser trimming and solid state switches. This is accomplished using micro-electromechanical system (MEMS) technology to integrate an amplifier and its tunable LC network on a common substrate. The LC network can be configured to provide a very narrow bandwidth frequency response which peaks at one or more very specific predetermined frequencies without de-Qing the oscillator.

Abstract: The frequency of oscillation of two cross-coupled CMOS inverters with a parallel LC tank connected between the two drains can be varied by a control voltage which varies the capacitance value of the tank circuit. The gate-to-source capacitance is used as the variable capacitance. The gate-to-source capacitance is varied by changing the dc gate voltage, which can be effected by either changing the dc current through the inverters or by varying the dc voltage across the inverters. The control voltage may also be made to vary with temperature such that the free running frequency of the oscillator is held constant with varying temperature.

Abstract: An oscillator is composed of a feedback circuit and an amplifying circuit. The feedback circuit has first and second terminals. The feedback circuit shifts a phase of a first signal inputted to the first terminal by substantially 180° to output a second signal from the second terminal. The amplifying circuit includes an inverter and a variable resistor element. The inverter has an output terminal and an input terminal. The output terminal of the inverter is electrically connected to the first terminal. The input terminal of the inverter is electrically connected to the second terminal. The variable resistor element has first and second variable resistor terminals. A resistance between the first and second variable resistor terminals is variable. The first variable resistor terminal is electrically connected to the first terminal and the second variable resistor terminal is electrically connected to the second terminal.

Abstract: An inductive proximity sensor oscillator having a differential comparator in combination with a negative feedback network and a positive feedback network connected to the comparator. The positive feedback network determines the frequency and amplitude of the generated oscillations. An LC resonant tank circuit is connected between a non-inverting input and a fixed reference voltage, and a current limiting resistor connected between the non-inverting input and the output of the comparator. The negative feedback network provides a simple, fast and reliable start-up mechanism. It comprises a capacitor connected between the inverting input of the comparator and the circuit ground and a resistor connected between the non-inverting input and output of the comparator.

Abstract: A circuit and method used in LC or ring oscillators. The present invention may modulate the frequency of oscillation by detecting a quadrature signal and controlling the sign and magnitude of the quadrature signal that may be feedback to the oscillator to cause the oscillator to run either faster or slower (dependent on the sign of the quadrature signal) than the unmodulated oscillator.

Abstract: A multiple band voltage controlled oscillator capable of generating multiple operating frequencies, and a method of generating multiple operating frequencies, includes a tank circuit having a diode element and an impedance element with a radio frequency impedance in parallel with the diode element, a PIN diode connected across a portion of the inductance of the impedance element which selectively shorts the portion of the inductance of the impedance element when activated, a switch connected to selectively enable the PIN diode and correspondingly partially short the inductance of the impedance element, thereby scaling the radio frequency impedance of the tank circuit, and an oscillator circuit responsively connected to the PIN diode for varying the output of the voltage controlled oscillator based on the radio-frequency impedance present.

Abstract: An AC tuning signal is injected into an LC tank circuit oscillator through an impedance (either reactive, inductive, capacitive and/or resistive) to tune the phase and/or frequency of the LC tank circuit oscillator. A negative resistance is included in parallel with the LC tank circuit oscillator to compensate for losses in the LC tank circuit, and a bias signal is provided to power the operation of the LC tank circuit. The AC tuning signal may be injected into the LC tank circuit using capacitors, resistors, FET or bipolar transistors, and/or inductors. Multiple LC tank circuit oscillators may be used to provide stable multiplied or divided frequencies. In this case, the output of one LC tank circuit oscillator may be used to tune another LC tank circuit oscillator. In another embodiment, the nominal frequency of the LC tank circuit oscillator may be adjusted using a varactor or other voltage-controlled element in the LC tank circuit oscillator under the control of, e.g.

Abstract: An oscillator having a tank circuit, an amplifier circuit and a switching circuit. The switching circuit switches the oscillator between a normal power consumption mode and a lower power consumption mode. The amplifier circuit includes an emitter biased transistor. The switching circuit switches between power consumption modes by switching between two selected voltages at the base of the transistor. When in the lower power consumption mode, the oscillator has sufficient current to sustain oscillation but insufficient current to meet the phase noise requirements for good fidelity and high data rates.

Abstract: A controllable LC oscillator circuit has a resonant circuit including an inductance and a capacitance disposed in parallel. The oscillator is driven by an amplifier and the inductance is produced using coupled coils. The effective inductance of the coupled coils can be set by changing a gain of the amplifier, and a magnitude of the coupling factor of the coupled coils defines a magnitude of an adjustable frequency band of the oscillator.

Abstract: An integrated circuit (shown below dashed line A--A) for a voltage controlled oscillator comprises a first transistor (T.sub.1) having its collector coupled to a first port (Port 1) via a filter comprising a capacitor (C.sub.f) and an inductor (L.sub.f) and its emitter coupled to the emitter of a second transistor (T.sub.2) whose collector is coupled to a second port (Port 2). The collector of the first transistor is also coupled via a capacitive divider (C.sub.1, C.sub.2) to the base of the second transistor. The base of the first transistor is AC decoupled (C.sub.3). The emitters of the first and second transistors are fed by a current source (I.sub.1). A capacitor (C.sub.s) connects the base of the second transistor to the first port. The first and second ports are for connection to an external resonator (L.sub.1, D.sub.1, C.sub.p, L.sub.p) (shown above dashed line A--A) where C.sub.p and L.sub.

Abstract: A method and apparatus for synthesizing high-frequency signals is disclosed that overcomes integration problem associated with prior implementations while meeting demanding phase noise and other impurity requirements. In one embodiment, a phase-locked loop (PLL) frequency synthesizer is disclosed having a voltage controlled oscillator (VCO) with a variable capacitance that includes a discretely variable capacitance in conjunction with a continuously variable capacitance. The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance, and the continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance. In a more general terms, a frequency synthesizer is disclosed having a first variable and a second capacitance circuits and frequency control circuitry to coarsely tune the output frequency by adjusting the first control signal and to finely tune the output frequency by adjusting the second control signal.

Abstract: A high frequency anharmonic oscillator provides a broad band chaotic oscillation with a noise-like spectra. The oscillator output signal is suitable for modulation by data providing for improved secure communication. The chaotic oscillator is based upon a forced second order Duffing equation that is tolerant of delay in the feedback path for high frequency operation.

Abstract: An oscillator is formed by a resonator (RES) coupled to an amplifier (AMP) via a coupling path (COP). In order to counter unwanted oscillations due to parasitic resonances in the coupling path (COP), the coupling path (COP) includes a series resistance (RS). This allows better performance in terms of noise for countering unwanted oscillations, despite the fact that the series resistance is in itself a source of noise. An even better noise-performance is obtained if the coupling path (COP) also includes a series capacitance. Such a series capacitance will also effectively widen a frequency range over which the oscillator can be tuned.

Abstract: A multi-band phase lock loop (PLL) device for use in a communication system. The PLL comprises a frequency reference oscillator, a reference frequency divider, a phase and frequency detector, a filter and compensation circuit, a microcontroller, a multi-band voltage controlled oscillator (VCO), and a feedback divider. A fast feedback signal is provided to the VCO for phase locking operation. A slow feedback signal is used by the microcontroller to generate a frequency adjust signal for frequency band centering for the VCO. The microcontroller also controls the VCO to change the frequency band of operation. The PLL device may be used in a communication system that operate in both the cellular frequency band and the PCS frequency band.

Abstract: A voltage controlled oscillator (1) comprising a voltage controllable variable resonant circuit (2) having a control input (Vctrl), a positive feedback input (6) and a controllable variable frequency output (7). The voltage controlled oscillator (1) also has an amplifier (3) having an amplifier input coupled to the controllable variable frequency output (7) and an oscillator output (Out). A positive feedback path (4) couples the amplifier (3) to the a positive feedback input (6) and a frequency dependent negative feedback path (5) provides increased negative feedback to the amplifier (3) as the Radio Frequency increases.

Abstract: In an oscillator comprising a resonant circuit (L, C, R.sub.CU) and an amplifier circuit (V, R.sub.1, R.sub.2, R.sub.3) connected as a negative resistance (R.sub.n), a direct current source (I.sub.1) is connected in series with the resonant circuit (L, C, R.sub.CU). In this way, a signal (U.sub.CU) is provided being a measure for the resistance of the oscillator circuit coil (L). By using this signal (U.sub.CU), a control circuit (V.sub.1, M; V.sub.2, V.sub.3, M) controls the negative resistance (R.sub.n) inversely proportional to the resistance (R.sub.CU) of the oscillator circuit coil (L). This affords a simple stabilization of the temperature behavior of the oscillator circuit (L, C, R.sub.CU) and allows the low price manufacture of inductive proximity switches having a great switching distance which function safely in a broad temperature range.

Abstract: An integrated circuit having at least the following: a substrate; a composite inductor formed within the substrate having at least a first coil with an associated first coil inductance and first coil resistance and a second coil with an associated second coil inductance and second coil resistance, with the first coil formed proximate the second coil for magnetic flux linkage such that when a current in the first coil is matched with a current in the second coil, a new inductance associated with the first coil is produced that is in excess of the first coil inductance. An oscillator can be formed in the integrated circuit by connecting the first coil to at least one capacitor formed in the substrate.

Abstract: A voltage controlled oscillator has a cross-coupled negative resistance cell formed as an integrated circuit connected to off-chip components of a high-Q resonant tank circuit. To counteract spurious oscillations brought about by package parasitics caused by the interconnection of the chip to the external components, the cell is provided with a degeneration impedance. Typically, a pure inductor is used if all the elements of the tank circuit are off-chip. In a case where the tank circuit includes an on-chip fixed capacitor, the degeneration impedance may take the form of a capacitor.

Abstract: A method and system in an integrated circuit for frequency tuning oscillator circuits. An oscillator circuit within an integrated circuit is formed on a substrate such that the oscillator circuit is coupled to an inductor component. The inductor component includes a first inductor positioned parallel to a second inductor such that a total effective inductance is associated with the first and second inductors. The first inductor is formed from a first spiral coil layer which is coupled to a second spiral coil layer on the substrate. The second inductor is formed of a single spiral coil layer on the substrate, wherein the single spiral coil layer provides an inductive feedback signal to the oscillator circuit when electrical current flows through the single spiral coil layer in response to current flowing through the first spiral coil layer and the second spiral coil layer.

Abstract: A resonance circuit includes a capacitor, a coil element and a primary coil of a transformer. A connection between the resonance circuit and a vehicle-mounted battery is connected and disconnected by a switching transistor at a predetermined duty cycle. Output voltage of a secondary coil of the transformer is supplied to an exciting winding of a resolver.

Abstract: A method and an apparatus for generating oscillating waveforms using adiabatic circuitry. In one embodiment, an LC oscillating circuit generates oscillating waveforms that are replenished with replenishing circuitry. The replenishing circuitry includes enable circuitry and circuitry that reduces short circuit currents that may flow through the replenishing circuit. Furthermore, the pull-up and pull-down devices of the replenishing circuit are gradually turned on and gradually turned off to reduce the introduction of glitches into the oscillating sinusoidal waveform of the oscillating circuit. A control circuit, such as a phase lock loop circuit, is included with the present invention to receive an external clock reference waveform and match the frequency and phase of the oscillating waveform in the oscillating circuit to the external clock reference waveform.

Abstract: A method is described for maintaining a constant Q in a voltage controlled oscillator (VCO) which is tuned over a broad frequency band. A tank circuit (111) sets a center frequency of an oscillator circuit (112). A variable reactance circuit (113) provides a variable effective reactance across the tank circuit (111) corresponding to an applied tuning voltage (117) for tuning the VCO. Resistive currents from the variable reactance circuit are rectified by a rectification circuit (120). A comparator produces a Q control voltage corresponding to the rectified resistive currents and a reference current Iref at a terminal (126) which is coupled to a variable resistance circuit (122) for supplying differential resistive currents to the tank circuit (111) which offset the resistive currents from the variable reactance circuit, thereby maintaining a constant Q in the VCO.

Abstract: A transformerless high-voltage generator circuit includes an amplifier and a feedback circuit connected together to form an oscillator. Due to the configuration of the feedback circuit, a high-voltage output is obtained at an intermediate point within the feedback circuit without the use of a transformer. The resulting circuit may be used in various applications, such as an electronic photoflash unit, in order to reduce the size, weight and cost of the finished product by eliminating the need for a transformer to obtain the desired high voltage.

Abstract: A relatively simple low-power-dissipation oscillator circuit comprises an inductor in series with a capacitor. Self-timing circuitry connected to an output node point between the inductor and the capacitor compensates for resistive losses in the circuit and thereby insures generation of a constant-amplitude output sine wave suitable for driving PPS CMOS circuitry. The oscillator circuit also includes starting and stopping circuitry connected to the inductor. To conserve power during so-called data inactive periods, the oscillator circuit can be abruptly stopped in a manner that preserves stored states in the CMOS circuitry and provides an output voltage suitable for powering conventional (non-PPS) CMOS circuitry while establishing a reliable basis for subsequently reinitiating oscillations.

Abstract: A variable frequency oscillator which can be implemented entirely in a semiconductor chip, which is variable over a broad frequency range and which has relatively low phase noise, includes a variable impedance circuit, a reactive load connected to an output terminal pair of the variable impedance circuit, and a negative impedance circuit having an output terminal pair connected to the output terminal pair of the variable impedance circuit. In one embodiment, the negative impedance circuit has an input terminal pair connected to an input terminal pair of the variable impedance circuit to serve as a positive feedback path for the variable impedance circuit. In another embodiment, the negative impedance circuit includes a pair of level shifters which ensure that the variable impedance circuit is properly biased and works in a forward active region.

Abstract: An oscillator, constructed partially within the confines of a monolithic integrated circuit, includes a differential-input, differential-output, differential amplifier within the monolithic integrated circuit. First and second resistive potential dividers located within the monolithic integrated circuit respectively divide the potentials appearing at the first and second output terminals of the differential amplifier in a predetermined ratio for respective application to the first and second input terminals of the differential amplifier, thereby respectively completing first and second direct-coupled regenerative feedback connections. An inductor located outside the monolithic integrated circuit is connected between the first and second input terminals of the differential amplifier and is anti-resonated by one or more capacitors, which may be located inside or outside the monolithic integrated circuit.

Abstract: An oscillator comprising an amplifier device, a capacitive divider bridge whose terminals are connected between a control electrode of the device and a reference voltage, the intermediate junction point of this bridge being connected to a principal electrode of the device, and also comprising, in parallel between the control electrode and the reference voltage, a tuning circuit having parallel branches: a first branch with an inductance in series with a variable capacitance, and, a second branch equivalent to a variable capacitance. The tuning circuit has a third branch constituted by a capacitance in parallel with the first branch, while a series inductance whose value is smaller than that of the tuning inductance is arranged between the junction point connecting the two latter branches and the junction point connecting the control electrode of the device to the second branch and to the divider bridge.

Abstract: In an electrosurgical generator having a self-tuning oscillator which includes a switching device and a resonant output network connected between the switching device and a supply rail, an oscillator feedback circuit feeds to the switching device a switching control pulse signal for separately switching the switching device to its "on" state whilst the voltage across the device is decreasing, the phase of the "on" point being dynamically variable such that the "on" time of the device is adjusted so as to regulate the amplitude of the voltage thereacross. This allows reverse conduction of the switching device to be avoided, giving improved efficiency.

Abstract: A compensation circuit including resistors, capacitors and a varactor diode powered simultaneously by the same voltage source applied to a voltage controlled oscillator for reducing deviation from a desired oscillator output frequency on power-up. When power is applied, an exponentially varying voltage is applied to the varactor diode changing its capacitance in such a manner as to change the oscillator frequency in the opposite direction to its natural drift tendency, thus producing a substantially constant output frequency over the period of interest.

Abstract: BiCMOS technology is used in the design of a VCO (200) to improve low DC operation. The VCO (200) includes two coupled oscillator circuits (201,219) tuned to different fixed frequencies such that the oscillator resonant frequencies define the tuning range of the VCO (200). The oscillator circuits (201, 219) are coupled such that the frequency of oscillation of the VCO (200) is adjustable via variable resistors (206, 214) by manipulating the bias currents to the two oscillator circuits (201,219). A biasing circuit (208) along with variable resistors (206 and 214) provide the DC bias to the oscillator circuits (201 and 219). The biasing circuit (208) maintains the sum of the biasing currents to the oscillator circuits constant. The oscillator circuits (201, and 219) are interconnected utilizing an RF coupling circuit (211). The VCO (200) is capable of operating at voltages as low as 1.8 volts DC.

Abstract: The present invention provides a resonance-type optical receiver circuit which keeps predetermined small distortion even when the received light level becomes high. The resonance-type optical receiver circuit varies the resistance value of variable resistance element 80, which is used as a load resistor to optical detector 4, in response to the intensity of output signal 10 of an amplifier. The load resistor varies in response to a variations of the received light level of the optical detector in this manner to keep the input to the amplifier lower than a fixed value.

Abstract: A voltage controlled oscillator provides a fixed amplitude output at an adjustable frequency. The voltage controlled oscillator includes a first transistor including an emitter, a base, and a collector. A first capacitor is connected between the emitter and the base of the first transistor. An inductance simulating device generates a controllable impedance and includes second and third transistors each with a base, an emitter, and a collector. The second and third transistors are connected between the base and the collector of the first transistor. The controllable impedance includes an inductive reactance component related to a quiescent bias current flowing through the third transistor. A current source connected to the third transistor generates the quiescent bias current to vary the inductive reactance component. The inductive reactance component and the first capacitor vary the adjustable frequency of oscillation.

Abstract: A self-excited solid-state oscillator for supplying a high-power RF inductive load. The oscillator includes at least one MOSFET transistor connected in a self-excited oscillator configuration, an output tuned circuit including an inductive load and a tank circuit connected to the load, the tank circuit having a resonant frequency determined at least in part by the inductance of the load, an RF feedback transformer coupling the tank circuit to the gate of the MOSFET for providing a switching signal to the MOSFET for causing the MOSFET to alternate between the on state and the off state at a frequency equal to the resonant frequency of the tank circuit, and a bias circuit for superimposing a forward bias voltage on the switching signal.

Abstract: A frequency synthesizer includes an oscillator which may be coarse-tuned by a first input receiving a digital signal for selecting one of a plurality of frequency ranges, and fine-tuned by a second input receiving an analog signal for selecting the desired frequency within the selected frequency range. The synthesizer further includes a computer storing the oscillator's characteristics in the form of a digital table of the input signals corresponding to a plurality of frequency values, each identified by digital data. The computer receives input data representing the desired oscillator frequency and generates from the stored digital table, a digital signal indicating the frequency range of the desired oscillator frequency, and an analog signal indicating the specific oscillator frequency desired, and applies both signals to the oscillator. A frequency measuring circuit measures the actual output frequency of the oscillator and outputs a signal corresponding thereto.

Abstract: A low-noise oscillator has a resonant circuit for generating a signal at a desired frequency. A linear amplifier and a limiter are electrically connected to the resonant circuit at first, second and third locations. A buffer amplifier is electrically connected to the resonant circuit at a fourth location and applies the signal generated by the resonant circuit to a load. The first, second, third and fourth locations are selected to minimize the impedance from those locations to ground at 1/f frequencies.

Abstract: An electrically controllable oscillator circuit (30) comprises two balanced transconductance circuits (G1, G2), each including transistor pairs arranged as inverters (Inv14) and as resistors (Inv5-6). The oscillation frequency (f) and the quality factor (Q) of the oscillator circuit (30) are controlled by means of a single control signal provided by a combined control circuit (Inv7, Dif, IM1, IM2). The current mirror circuit (IM1, IM2) and a differential pair (Dif) derived the control signal for adjusting the quality factor (Q) from a resistor-connected further transistor pair (Inv7) connected to the control signal for adjusting the frequency (f). The quality factor of an electrically controllable filter arangement including similar transconductance circuits (G-3-9) is adjusted by means of the control signal generated by the control circuit via a buffer circuit (B) and a low-pass circuit (C3).

Abstract: A high-frequency electron tube power oscillator includes a multi-grid electron tube (1) in which the output power is adjusted by means of an adjustable impedance element (5) connected in series with the cathode line of the tetrode (1). In order to reduce the dissipated power in the adjustable impedance element (5), the voltage across the impedance element is connected to the screen grid of the tetrode (1) through an amplifier (6) constituted by a triode (9) and a current source (10).

Abstract: A balanced oscillator circuit having first and second outputs includes a transistor circuit, having internal parasitic capacitors, for providing first and second output signals at the first and second outputs of the balanced oscillator circuit. An inductor circuit is coupled between the first and second outputs such that the inductor circuit and the internal parasitic capacitors determine the frequency of oscillation of the first and second output signals. The capacitance of the internal parasitic capacitors can be varied by an external voltage applied to the transistor circuit.

Abstract: Three series connected inverters (38, 40, 42) are attached to a tank circuit (18) which includes an inductance (12, 14) and a capacitance (16, 17). Negative (38) biases the inverters at the midpoint between the bistable low and high logic level states. Positive feedback from the second inverter (40) to the tank circuit induces oscillation in the tank circuit. The negative feedback is decoupled at the resonant frequency and the energy delivered to the tank circuit from the positive feedback maintains a low level oscillation in the tank circuit. Negative feedback around the three inverter digital circuit prevents lockup in the event of power loss or momentary short.

Abstract: The electronically tuned power oscillator (ETPO) of the present invention provides a method and apparatus that drives a narrow-band (high Q) transducer over a relatively broad band of frequencies. A pseudo-random sequence generator dynamically switches a bank of capacitors varying the resonant frequency of the power oscillator. A node on the power oscillator provides the clock for the pseudo-random sequence generator thereby providing a synchronized frequency change on every time varying cycle.

Abstract: The temperature dependency of an oscillator can be reduced by a method and circuit that uses two positive feedback paths to provide the positive feedback necessary for maintaining the oscillation of an LC-oscillating circuit. One of the two feedback paths compensates the temperature dependent influences while the other compensates temperature independent influences.

Abstract: A high-frequency power oscillator is built around a power amplifier utilizing semiconductors in a complementary or quasi-complementary stage which operate in a switching mode of operation. The output of the amplifier supplies high-frequency oscillations to a load impedance through an output filter composed of a series-resonant circuit and a parallel-resonant circuit. A feedback driving voltage is obtained from the output filter in a manner providing a first portion of the driving voltage from a voltage present in the parallel-resonant circuit for voltage feedback and a second portion of the driving voltage obtained by current inverse feedback from the current in the series-resonant circuit. These two components of the driving voltage are combined in an addition circuit and supplied to an input of the power amplifier through a pulse modification stage.

Abstract: A low-noise oscillator includes a resonator constituted by a coil, a capacitor and a sustaining coil which are made of superconductivity material and maintained at a low temperature below the critical temperature; a linear amplifier which always operates in its linear zone; and a load.The amplitude of oscillation is stabilized when it has attained a threshold value such that the superconducting material constituting the coil of the resonator becomes progressively resistive under the action of the magnetic field produced by this coil. The coil then dissipates part of the energy injected into the resonator. Since the high-frequency noise of the oscillator is essentially determined by the low-frequency noise of its nonlinear element, the use of superconducting material at low temperature in order to constitute the nonlinear element makes it possible to obtain an oscillator having very low noise.

Abstract: In a high-frequency generator (1) comprising a multigrid electron tube (2), the control grid (3) and the screen grid (4) are substantially d.c. coupled. The tube then oscillates via the internal parasitic capacitance between the screen grid (4) and anode (5) without requiring an external feedback circuit. A reduction of the heat dissipation and a compact electron tube are the result with high oscillation frequencies likewise being attainable. A high-frequency decoupling of the control grid (3), with an intermittent operation of the generator (1), results in a very limited heat dissipation, causing the generator (1) to be very compact.