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: A voltage control oscillator capable of obtaining the desired output voltage by lowering the higher order harmonic level, is provided. Further, in the voltage control oscillator, a resonance circuit achieves the resonance by switching two different resonance frequencies. Moreover, inductors of a matching circuit are selectively used to change the inductance by turning on/turning off a diode of an impedance regulation circuit according to the respectively switched frequencies. Furthermore, the synthesized impedance with a matching capacitor is changed to achieve the matching with each of two frequencies.

Abstract: The invention relates to an oscillator OSC intended to provide an output signal having a frequency which is variable as a function of a tuning voltage Vtun. The oscillator OSC includes a passive part having two series-arranged variable capacitances Cs, biased by the tuning voltage Vtun, and connected to a power supply VCC via two inductances Lext, and an active part having a first transistor T1 and a second transistor T2 whose collectors are connected to the output terminals C1 and C2 of the passive part, the base of one transistor being connected to the collector of the other transistor via a coupling capacitor Cfb. According to the invention, the passive part includes two high-pass filters, each being inserted between one of the output terminals S1 or S2 and one of the variable capacitances Cs, which allows a reduction of the active part's sensitivity to low-frequency noise.

Abstract: A transmitter VCO (204) includes nodes for receiving a band selector voltage for altering the base-emitter capactance of a transistor to enable the VCO to act as an oscillator in the appropriate band, and for altering the resonator capacitance to change the resonant frequency of the oscillator. The method and apparatus enables oscillation in different frequency bands for dual mode communication devices.

Abstract: An active inductor oscillator includes a tank circuit for generating a first differential signal, a common-mode inverting differential buffer for generating a second differential signal in response to the first differential signal, and an integrating circuit for generating a third differential signal in response to the second differential signal. The third differential signal is applied to the tank circuit, and lags the first differential signal. A differential transistor pair in the tank circuit provides active inductance in response to the third differential signal, and a cross-coupled transistor pair in the tank circuit provides negative resistance that amplifies the first differential signal in response to the first differential signal. Currents through the tank circuit, buffer, and integrating circuit are essentially identical to one another and move in unison with an externally applied reference current that controls the oscillation frequency.

Abstract: An integrated oscillation circuit used for frequency conversion circuit in which UHF frequency conversion and VHF frequency conversion are selectively energized to use a common IF amplifier. The integrated oscillation circuit is used for a local oscillation circuit. The integrated oscillation circuit including a connection terminal connected to an external resonance circuit and an input line of a mode switching signal which is set at a different level in response to an operation mode, an oscillation element, a bias terminal of which is connected to the connection terminal, a detection circuit detecting the level of the mode switching signal applied to the bias terminal of the oscillation element, and a switching circuit turning on and off a power source for driving the oscillation element in response to the level detected at the detection circuit.

Abstract: A voltage-controlled oscillator has first and second switched capacitor filters, an operational amplifier, and a comparator. The first switched capacitor filter is controlled by a control clock signal to supply a positive current depending on an input voltage, and the second switched capacitor filter is controlled by the control clock signal to supply a negative current depending on the input voltage. The operational amplifier has an input terminal alternately connectable to the first and second switched capacitor filters by a first switch which can be rendered conductive in synchronism with an output clock signal, and another input terminal for being supplied with a constant voltage.

Abstract: A transmitting and receiving apparatus configured in superheterodyne form, includes a receiving circuit for receiving a signal on one channel of a predetermined pair of channels and a transmitting circuit for transmitting a signal on the other channel of the predetermined pair of channels. The receiving circuit has a first voltage-controlled oscillator including a first oscillating transistor and generating a local oscillated signal used for receiving the signal on one of the channels, and a first current control means for controlling a collector current of the first oscillating transistor. The transmitting circuit has a second voltage-controlled oscillator including a second oscillating transistor and generating a signal of the frequency of the other channel, and a second current control means for controlling a collector current of the second oscillating transistor.

Abstract: A high power, low noise voltage-controlled oscillator (VCO) eliminates the drive-stage amplifier and costly surface-acoustic wave (SAW) inter-stage filter in a transmitter such as a cellular radiotelephone. The VCO includes a resonant circuit, an active part connected to the resonant circuit, and a buffer amplifier, connected to the active part, for isolating the VCO from a load connected to the buffer amplifier. The active part includes at least one transistor in a Colpitts configuration; capacitances connected in parallel with junction capacitances of the transistor, each capacitance having a value that is greater than a value of the respective junction capacitance with which it is connected in parallel; and a resistance for providing negative feedback at low frequencies. A second resistance may be provided for reducing the gain of the active part when oscillation starts.

Abstract: According to the preferred embodiment, a self-biased phase-locked loop is provided that overcomes the limitations of the prior art bias methods and apparatus. In general, a self-biased current controlled semiconductor device, typically a current controlled oscillator, is self biased by the use of a first feedback path, typically provided by a phase-locked loop, where the feedback path provides a control current for controlling the current controlled device. A second feedback path, typically a pair current mirrors, serves as a bias loop having unity gain. The bias loop provides a bias current that is responsive to the control current. This device has the advantage of being self biasing, thus no other biasing circuitry is required.

Abstract: A ring oscillator having an odd number of single ended stages, each stage including two transistors connected as a current mirror. The stage provides for low-voltage performance and improved process tolerance characteristics.

Abstract: A voltage-controlled capacitor includes a multiplier, having an output which serves as terminals of the controlled capacitor. The output voltage of the multiplier is applied to a reference capacitor. A signal in phase with the current in the reference capacitor is applied at one input of the multiplier, the other input of the multiplier receiving a signal determining the value of the controlled capacitor.

Abstract: A microwave generator has its microwave frequency optically phase-locked by means of a reference frequency of a reference signal, wherein at least one portion of an electronic circuit arrangement is supplied with an optical reference carrier signal modulated with the reference frequency. The circuit arrangement (16) includes two components (Q1 to Q6; Q10, Q11) based on different semiconductor types which are chosen so that one of them, the first component, which is of a first semiconductor type, optically responds to the reference carrier signal (3) and, thus, to the reference frequency (f.sub.1 Mod1. . . Modn) for achieving synchronization, and that--independently of the response of the first component--the other, second component, which is of a second semiconductor type, responds to an optical control carrier signal (6) differing in frequency from the reference carrier signal (3).

Abstract: A multiphase clock generator which exhibits frequency stability in the presence of power supply noise. The clock generator of the present invention includes a phase detector for generating a phase error signal in response to the phase difference between an input signal and a recovered clock signal. A phase-locked feedback loop is operative to synthesize a recovered clock signal in response to the phase error signal. Included within the feedback loop is a differential ring oscillator disposed to provide first and second phase-shifted output signals at first and second output ports. The addition of a combination network to the multiphase clock generator of the present invention allows a multiplied clock signal to be derived from an input signal. Specifically, the phase-locked feedback loop 18 included within the clock multiplier of the present invention provides a plurality of sequentially phase-shifted waveforms at a first multiple of the frequency of the input signal.

Abstract: A frequency synthesizer, which controls the fluctuation of frequency not only of a long period but also a short period, ensures a wide frequency control range and can be realized at a low cost, can be obtained.

Abstract: An optically controlled active impedance element particularly suited to se as a tuneable inductive element for a microwave oscillator is disclosed. The optically controlled active inductive element is comprised of a circuit arrangement, preferably consisting of MESFET devices which exhibit a composite inductive characteristics, and whose inductance may be determined and controlled by direct illumination impinging on the MESFETs. The optically controlled active inductive element lends itself to being adapted to monolithic microwave integrated circuit (MMIC) applications and may find use in a wide variety of microwave circuits. Also disclosed, is an embodiment which used the optical controlled active impedance element, in a prescribed manner, to serve as a tuneable capacitor for use in various microwave circuits.

Abstract: An oscillator circuit uses a differential oscillator and differential amplifier to generate a symmetrical single-ended output signal. The differential oscillator generates a differential oscillator signal having an adjustable zero-crossing point in response to a control signal. The differential amplifier converts the differential oscillator signal to the symmetrical single-ended output signal having a symmetrical waveform. Controlling the zero-crossing of the differential oscillator signal compensates for common mode variation in the differential amplifier and produces a single-ended output signal having a symmetrical waveform with 50% duty cycle. A matching amplifier operating in a self biasing mode produces the control signal.

Abstract: An automatic voltage-controlled oscillator (VCO) current control circuit, that senses a voltage in the VCO representative of the current of the VCO, compares that voltage to a reference voltage, and applies the voltage resulting from that comparison back to the VCO at a point therein that changes its bias state in such a manner as to maintain the noise level in the VCO at a minimum and also maintains the power output of the oscillator substantially constant.

Abstract: An oscillation circuit for an integrated circuit device. The oscillation circuit includes a band-pass filter for producing an output signal having a voltage and a defined resonance frequency and a voltage to current converter type limiter amplifier connected to the band-pass filter for supplying a current to the band-pass filter corresponding to the voltage of the output signal of the band-pass filter.

Abstract: An improved oscillator circuit utilizing multiple semiconductor devices, such as field-effect transistors or bipolar transistors, is disclosed. To improve the gain of the oscillator circuit corresponding terminals on each device are interconnected via a path which provides a delay equal to an integer multiple of the inverse of the oscillator frequency. This technique can be adapted to provide an oscillator whose nominal frequency is voltage controllable and can be arranged to provide one or more output ports.

Abstract: A circuit for generating a succession of fast rising voltage pulses comprises an inductor connected between first and second circuit nodes, a step recovery diode connected between a reference potential level and the first circuit node, and a current switch having a first state in which it conducts current in one direction with respect to the second circuit node and a second state in which it conducts current in the opposite direction with respect to the second circuit node. An oscillator is connected to the current switch for alternately and repeatedly placing the current switch in its first state and its second state. Preferably, the oscillator comprises a SAW resonator having a high Q and a parallel LC tank circuit having a low Q, connected in a closed positive feedback loop.

Abstract: Three-terminal negative admittance networks are disclosed. The preferred networks include either a bipolar junction transistor or a field-effect transistor phase shift mechanisms are used to generate a negative admittance. Various biasing schemes for proper operations of the network are also explained.

Abstract: Voltage controlled oscillator (50) provides an exponential transfer function. The frequency of the output signal of the voltage controlled oscillator varies exponentially with the input voltages (V.sub.IN1, V.sub.IN2) to the oscillator. The exponential transfer characteristic is provided by means of a MOS field effect transistor (19) biased in its subthreshold range.

Abstract: The disclosure relates to a gallium arsenide travelling-wave transistor oscillator which extends the oscillation frequency of the individual FETs by connecting them in parallel across a pair of inductive arrangements, either in common-gate or common-source configurations.

Abstract: A television signal generator for producing a composite RF signal without high level intermodulation products. A signal network is provided to linearly combine a first video modulated carrier signal and a second carrier frequency of the same frequency modulated with an audio modulated subcarrier. An audio subcarrier generator is disclosed having a ceramic resonator for a frequency determining circuit element. The resonator is parallel connected with a voltage sensitive reactance element to provide a frequency modulated subcarrier in response to a modulating voltage.

Abstract: An oscillator circuit operable in different modes. The oscillator circuit, when operated as a crystal oscillator, is initially operated as a standard inverter oscillator requiring a low start-up voltage. Once the circuit oscillates, an hysteresis feedback network is inserted in the amplifying section of the oscillator providing a clock signal with sharper leading and falling edges. The circuit thus enables the start up of the oscillator at low voltages and ensures greater noise immunity following start-up. The oscillator circuit, when operated as an RC oscillator, may be operated as a Schmitt-trigger oscillator as soon as the oscillator is turned-on.

Abstract: A supporting plate having a network of conductors, on which supporting plate a number of circuit components are placed which are interconnected in the network of conductors in an electric circuit. In a place of the circuit which is sensitive to moisture, a board opening is provided in which a member of a minimum moisture-absorbing material is fitted. The connections of the surrounding circuit components extend in an aperture of the member and are electrically interconnected there. The stability of the circuit is considerably improved thereby in particular in the case in which the circuit is an oscillator circuit.

Abstract: The gain margin of a junction FET oscillator is improved by the addition thereto of a bipolar transistor in parallel with the FET for boosting the closed loop circuit gain of the oscillator without degrading the phase noise performance of the FET. The oscillator circuit is formed by a grounded gate JFET with a feedback circuit including the internal impedance of the FET, a capacitor which couples source and drain of the FET, a capacitor which couples the FET source to ground, and a resonant circuit coupled between the drain of the FET and ground including a varactor diode for controlling the oscillating frequency and providing a circuit output. A bipolar transistor is coupled in parallel with the FET by coupling its collector to FET's drain and its emitter to the FET's source. The base of the transistor is coupled via a by-pass capacitor to circuit ground.

Abstract: To switch a first gated diode switch (GDS1) to the "OFF" state requires a voltage applied to the gate which is more positive than that of the anode or cathode and a sourcing of current into the gate of substantially the same order of magnitude as flows between the anode and cathode of the first switch. Control circuitry, which uses a second gated diode switch (GDSC) coupled by the cathode to the gate of the first switch (GDS1), is used to control the state of the first switch (GDS1). The control circuitry comprises a first branch circuit coupled to the gate of GDSC and to a first potential source +V1 and a second branch circuit coupled to the anode of GDSC and to a second potential source V2. The first branch circuit is connected to the gate of the second switch (GDSC) and controls the state thereof. The second branch circuit helps switch the first switch to the OFF state by providing a single current pulse or a plurality of current pulses into the gate of the first switch.

Abstract: A gated oscillator implemented with cascade-connected inverting logic circuits and resistor-capacitor timing elements generates oscillations so long as an inhibiting signal is not applied to one of the logic circuits. Means are provided to maintain potentials on the timing elements during application of inhibiting signal, which potentials are equivalent to steady-state operating potentials at the inception of a state transition. When the inhibiting signal is discontinued allowing oscillations to be generated, the initial pulse period is equal to the steady-state pulse period.

Abstract: An intrusion alarm having an oscillator which is turned off by the body capacitance of a would-be intruder operates in the frequency range of 17-65 MHz. At this frequency, reliable discrimination between body capacitance and stray capacitance is possible and therefore sensitivity is increased while false alarms are reduced. Battery life is increased by providing a high resistance load in the stand-by mode to reduce battery drain to 500 microamperes or less. Latching and nonlatching embodiments are disclosed.

Abstract: A common-drain high frequency power oscillator is configured by electrically reversing the channel of a GaAsFET transistor. Such an oscillator can be flip-chip mounted for reduced thermal resistance and has superior oscillation characteristics as compared with conventional common-source oscillators. Specifically, its gain is nearly constant with frequency, oscillation is less critically dependent on terminal impedance, and it can be operated with a single polarity voltage supply.

Abstract: Disclosed is a monolithic oscillator circuit which relies upon the thermal characteristics of the semiconductor chip for oscillation. The circuit includes, in one embodiment, first and second transistors with similar output characteristics coupled to the input of a comparator element, and a third transistor coupled to the output of the comparator. The first and second transistors are unbalanced and the third transistor is placed close to only one of these transistors so that any heat generated will primarily affect the output of only the adjacent transistor. Thus, when a current flows from the comparator through the third transistor, the generated heat will decrease the potential across the first and second transistors until they are balanced, and the current through the comparator will shut off. The current remains off until the transistor cools off and an unbalanced condition is again achieved.

Abstract: A compensation circuit for electronic circuits such as pulse generator circuits which are suitable for MOSICS includes a resistor of high resistance and parallel-connected MOSFETs of the enhancement type and depletion type, respectively. The drain electrodes of the MOSFETs are connected to a power supply through the resistor, and are also connected to the gate electrode of load MOSFET of the depletion type which constitutes a load for a MOSFET of the enhancement type. To the gate of the former enhancement type MOSFET, a controlled bias voltage is applied from the connection point of MOSFETs connected in series between the power supply and ground. By employing the compensation circuit in pulse generator circuits, the instability of the oscillating periods due to changes in the ambient temperature and changes in the supply voltage is compensated. Also, the differences of oscillating periods are decreased among MOSICs.

Abstract: This microwave circuit incorporates a transistor structure that provides either a two port amplifier or an injection frequency locked oscillator. This circuit eliminates circulators employed with Gunn and Impatt diode amplifiers and injection frequency locked oscillators. The collector-base junction is reverse biased so that the collector region functions either in the Impatt mode or in the transferred electron mode. An RF input signal is applied across the forward biased emitter-base junction. With a load across the collector-base junction having a conductance equal to the absolute value of the negative conductance generated by the collector region, the circuit functions as an oscillator at a frequency which is injection locked to the frequency of the input signal. With a load of increased conductance to suppress oscillations, i.e. overload the collector region, the circuit functions as an amplifier.