Abstract: An oscillator is provided for use in integrated circuits of the type that are employed in various, relatively low power, power management systems such as can be found in mobile communications systems and the like. The oscillator provides an output frequency that is highly stable over a range of conventional operational parameters. The oscillator provides a current generator that is comprised of a pair of NMOS transistors and a pair of PMOS transistors that are arranged such that the respective gates of each pair are connected to one another to establish current mirroring. The current generator is connected to a hysteresis circuit, which is operable to develop a potential difference in the circuit. The hysteresis circuit includes an NMOS transistor and a PMOS transistor that are respectively and correspondingly coupled to the current-mirroring NMOS and PMOS transistor pairs of the current generator.

Abstract: An oscillator is isolated from external mechanical and thermal effects by surrounding the oscillator on all sides with a thermally insulating medium such as an aerogel insulation structure that provides both thermal insulation and vibrational isolation. Power is supplied to the crystal oscillator without wires. Wires are eliminated by using modulated microwaves or millimeter waves to transmit power and signals into and out of the oscillators, such as with small, efficient transceivers utilizing microwave or millimeter-wave integrated circuits or use of solid-state light sources and photodetectors in combination with thermal insulation which is transparent to the wavelengths of the electromagnetic radiation.

Abstract: Chip logic, a frequency multiplication and/or division, a temperature sensing circuit, and a power management circuit, are integrated on a very large scale integrated (VLSI) circuit chip. The temperature sensing circuit directly measures the chip temperature, producing a temperature output signal. The power management circuit, which is connected to the temperature sensing circuit and to the chip logic, responds to the temperature output signal and to a functional state of the chip logic to generate a control signal to the PLL. The PLL responds to the control signal to either stop the clock signal or modify the operating frequency of the clock signal, depending upon the state of the control signal.

Abstract: A temperature compensated crystal oscillator (10), has a crystal oscillator circuit (12), a voltage controlled reactance element (30), a temperature compensation network (50), and a programmable DC-DC converter network (60) having an output (62) connected to the voltage controlled reactance element (30), or the temperature compensation network (50) or both. The DC-DC converter network (60) provides the capability of operating over an extended voltage range, by increasing the supply voltage to a level necessary to operate the voltage controlled reactance element (30). Much of this structure is adapted for use in an integrated circuit, and provides the advantages of minimizing power and current consumption.

Abstract: The present invention relates to a PLL frequency synthesizer including an A-D converter for receiving a frequency control voltage for a voltage-controlled oscillator for outputting a desired frequency in a frequency stable state, and converting the frequency control voltage into a corresponding digital signal and outputting the digital signal, a storage unit for storing a signal value of the digital signal, a D-A converter for converting the signal value into a corresponding analog signal and outputting the analog signal, a control unit for controlling input of the frequency control voltage to the A-D converter, reading of the signal value from the storage unit, and output of the analog signal from the D-A converter, and a loop filter for applying an output voltage of the analog signal to the voltage-controlled oscillator by the control unit before the synthesizer is started, and a high-speed frequency lock method using this synthesizer.

Abstract: A temperature compensated crystal oscillator including: an oscillation circuit having a quartz crystal resonator and a control terminal, for providing an oscillating signal determined by the quartz crystal resonator and a control signal, the control signal being applied to the control terminal; a temperature detecting circuit for detecting an operation temperature and outputting a temperature signal based on the operation temperature; and a control signal generating circuit for receiving the temperature signal from the temperature detecting circuit, generating the control signal based on a characteristic curve, and outputting the control signal to the control terminal; the characteristic curve essentially consisting of a plurality of straight lines and being an approximation of an ideal control curve in a predetermined operation temperature range including the operation temperature, the ideal control curve having a relationship between the control signal and the temperature signal for ideally compensating a f

Abstract: The oscillation circuit 30 has the two input terminals 32a and 32b connected to the piezoelectric elements 3a and 3b of vibrator 1. These input terminals 32a and 32b are connected to the two input terminals of the adder 36 via the buffers 34a and 34b. The output terminal of the adder 36 is connected to the inversion input terminal of the operational amplifier 44 used as a comparator and the input terminal of the control signal generator 46. The output terminal of the operational amplifier 44 is connected to the collector of the transistor 62 and the output terminal of the control signal generator 46 is connected to the base of the transistor 62. The emitter of the transistor 62 is connected to the output terminal 80 via the phase-shifting circuit 70. The output terminal 80 of the oscillation circuit 30 is connected to the piezoelectric element 3c of the vibrator 1.

Abstract: A pulse signal generating circuit includes a ring oscillator and an internal voltage generating circuit. The internal voltage generating circuit generates an internal voltage depending on an operation temperature. The internal voltage is low at a normal temperature, and is high at a high temperature. Each inverter in the ring oscillator is driven by the internal voltage supplied from the internal voltage generating circuit. Thereby, a period of a pulse signal increases at a normal temperature, and decreases at a high temperature.

Abstract: A novel bias generator circuit for a voltage controlled oscillator is described. The bias generator allows the VCO frequency to be made essentially independent of the supply voltage and temperature.

Abstract: A modified temperature compensation signal (110) is provided in a temperature compensated crystal oscillator (TCXO) circuit (100) in the following manner. A temperature dependent current generator (104) produces a temperature compensation signal (108) whose amplitude changes responsive to changes in ambient temperature. The temperature compensation signal (108) is scaled, based on a plurality of discrete frequency adjust values (212), to produce the modified temperature compensation signal (110).

Abstract: A differential mode voltage controlled oscillator (VCO) includes an odd number of delay cells. Each delay cell has a pair of input terminals and a pair of output terminals with the input terminals of each delay cell being connected to the output terminals of a preceding delay cell in a ring. Each delay cell has a delay time for inverting a complementary pair of signals from which a clock signal is derived. A positive temperature coefficient voltage-to-current converter receives the control voltage of the VCO and controls the maximum currents (and therefore the delays) of the delay cells. A pair of cross-coupling transistors in each delay cell keeps the signals on the output terminals out of phase (complementary). The cross-coupling transistors have sizes which maximize gain of the delay cells at the threshold voltages of the cross-couple transistor and thereby increase output voltage swing at high frequencies.

Abstract: A Colpitts-type oscillation circuit, employing a ceramic resonator vibrating in the energy trapping thickness shear slide mode is disclosed in which, an antiresonance frequency of the ceramic resonator has a negative temperature characteristic which is less step than that of its resonance frequency. Capacitance between terminals of the ceramic resonator is set so that an oscillation frequency (Fosc) of the oscillation circuit at the ordinary temperature is higher than a central frequency ((Fr+Fa)/2) of the ceramic resonator. Thus, it is possible to employ a ceramic resonator having a large bandwidth (.DELTA.F), thereby improving the temperature characteristic of the oscillation frequency.

Abstract: Solving the aging problem of crystal oscillators by doing field recalibration. The solution is to utilize an accurate external reference signal to determine when the frequency of the digital temperature compensated crystal oscillator (DTCXO) has drifted from the reference signal in excess of a specification. When this occurs, the DTCXO has used its internal compensation values to correct its output hence the difference between the external reference signal and the frequency of the DTCXO in excess of the specification is due to aging. A new compensation value for the present temperature is calculated using the reference signal. Using the well known fact that the temperature aging uniformly shifts the frequency over the temperature range, a controller utilizes the difference between the new compensation value and the stored compensation value for the present temperature to shift the entire set of compensation values to compensate for the aging effect.

Abstract: A frequency synthesizer, including a phase-locked loop. The phase locked loop effects phase comparison between a comparison signal based on an output from a voltage-controlled oscillator and a reference signal based on an output from a reference oscillator. The resultant phase difference signal is submitted to a loop filter whose output serves as a control signal of the voltage-controlled oscillator. The frequency synthesizer includes a preset circuit for switching the output of the voltage-controlled oscillator by quickly charging or discharging a capacitor of the loop filter and a modifying circuit for modifying the time constant of the loop filter. The phase-locked loop is brought to phase lock at a high speed by decreasing the time constant of the loop filter when switching the output frequency.

Abstract: An oscillator circuit with enhanced frequency characteristics is provided. This oscillator circuit includes a buffer (102) to amplify the output signal and provide a positive feedback, an inverter (106) to provide negative feedback to cause oscillation, a capacitive divider circuit (110, 112) for charge storage, a resistor (116) to provide controlled discharge, and a diode circuit (114) for providing frequency stability. Since frequency stability is included within the oscillator circuit, there may be no need to perform resistor trimming at the time of manufacture. Further, the capacitive divider circuit eliminates parasitic charge injection.

Abstract: A voltage control oscillation circuit comprises an oscillation loop and a control current generating circuit. The oscillation loop comprises: a first charge-discharge circuit including a first transistor circuit for converting a reverse voltage signal as a first input voltage into a first charge-discharge current according to a first conversion ratio, and a first capacitor which is charged and discharged by the first charge-discharge current for generating a first charge-discharge voltage signal; a second charge-discharge circuit including a second transistor circuit for converting the first charge-discharge voltage signal as a second input voltage into a second charge-discharge current according to a second conversion ratio, and a second capacitor which is charged and discharged by the second charge-discharge current for generating a second charge-discharge voltage signal; and a reverse circuit for reversing the second charge-discharge voltage signal into the reverse voltage signal.

Abstract: A Field Effect Transistor (FET) signal delay system with increased propagation delay time stability. This is accomplished by using a controlled voltage supply to power the amplifier stage. This voltage changes as the FET amplifier temperature increases in order to reduce the variation in propagation delay time, caused by the amplifier's gain and phase shift changes. By using this compensated amplifier as the delay element of a signal delay system, the propagation delay time stability is increased.

Abstract: Electronic apparatus generates first and second output signals having a quadrature phase relationship therebetween. A local oscillator signal with a reference phase is applied as an input to first and second signal branches. The second signal branch includes a phase control circuit for subjecting input signals passing therethrough to a determined phase shift. The phase control circuit is responsive to an applied DC control signal to adjust any phase shift error through the phase shift circuit from a predetermined phase shift to assure that the second output signal exhibits the required quadrature phase relationship to the first output signal. A memory/microprocessor combination stores a digital value that is indicative of a DC control signal which must be applied to the control circuit to alter the phase shift through the phase control circuit to the predetermined phase shift. The microprocessor accesses the digital parameter and applies it to the phase control circuit through a digital to analog converter.

Abstract: An emitter-coupled oscillator circuit suitable for monolithic integration.

Abstract: A phase-locked loop with memory storing control data. The control data to be given to a voltage-controlled oscillator in a phase-locked loop is addressed in accordance with an oscillation condition including the frequency of a reference signal, a dividing ratio of the frequency divider and ambient air temperature. When the phase-locked loop is controlled off, the control voltage for the voltage-controlled oscillator is changed into digital data by an analog-to-digital converter to be transferred to the memory. The digital data or control data is read out from the memory when the phase-locked loop is controlled on. The control data is then changed into analog equivalent as control voltage supplied to the voltage-controlled oscillator, shortening the locking-up time.

Abstract: A stabilized oscillation circuit includes a bias circuit which controllably biases a bipolar-transistor-driven crystal oscillator circuit. The bipolar-transistor-driven crystal oscillator circuit is a modified version of a conventional transistor-driven oscillator, such as a Hartley, Pierce or Colpitts-type circuit. The bias circuit includes a first current providing a reference current through a Schottky diode and a pair of bipolar transistors. The bipolar-transistor-driven crystal oscillator circuit includes an input and an output, where the input of the bipolar-transistor-driven crystal oscillator circuit is coupled to the bias circuit. The bipolar-transistor-driven crystal oscillator circuit includes a second current through a second bipolar transistor. The second current tracks the reference current so that the output of the bipolar-transistor-driven oscillator circuit is substantially constant over variations in ambient temperature.

Abstract: A thermally compensating microwave cavity is provided. An active device that generates microwaves is disposed within this microwave cavity such that microwaves are emitted within the cavity. A first portion of these microwaves travels in one direction from the active device and forms a broad bandwidth signal. A section portion of the microwaves travels toward a reflecting member and is reflected. Once reflected, this second portion combines with and compensates the first portion. A temperature dependent bellows is utilized to displace the active device and the reflecting member relative to one another. Accordingly, as the signal emitted by the active device changes with temperature, the reflecting member is displaced by the bellows to properly reflect the second portion of the microwaves such that it combines with and properly compensates the signal.

Abstract: A system and method for compensating in real time the dynamic power variation of a computer chip containing CMOS devices is provided. The present invention functions to control the temperature variations on the chip thus eliminating the drift to analog signals associated with CMOS devices. The present invention controls the temperature with the use of a compensation heater located on the CMOS chip. The compensation heater is driven by a plurality of signals which act in harmony with one another to control the temperature on the chip when it becomes unstable. The system and method includes driving the compensation heater with a maximum dynamic power value to effectively maintain the temperature on the chip, evaluating the chip for temperature fluctuation, and compensating for the temperature fluctuation by driving the compensation heater with at least one compensation power value.

Abstract: A method of directly bonding a crystal to a crystal includes the steps of mirror-polishing the surfaces of the crystals and then rinsing them with a cleaning material and then affecting a baking operation and then bonding them together and thereafter annealing them within a temperature range where crystal crystallization is not transited in phase so that a further strong bonding force is obtained. A crystal resonator is obtained where electrodes are oppositely established across a ply crystal blank with at least two sheets of crystal blanks having a desired cut angle and a desired thickness being directly bonded so that the respective crystal axes intersect at the desired angles. The ply crystal blank may have a central portion which is either thicker or thinner than a surrounding portion.

Abstract: A multirange low-gain voltage controlled ring oscillator generates a substantially temperature-independent oscillator signal. Each frequency range is formed by utilizing a selected value of a voltage variable resistance in each stage of the ring oscillator. The oscillator signal is made to be substantially temperature-independent by utilizing a substantially temperature-independent constant current source to source a fixed current through the variable resistance and a temperature varying current which sinks and sources additional current to the oscillating circuit as temperature rises and falls, respectively.

Abstract: A multimode oscillator is disclosed which employs a single gain loop for exciting at least two modes of a resonator to cause the oscillator to oscillate simultaneously at at least two frequencies. The multimode oscillator comprises the resonator, an amplifier to provide gain at the appropriate operating frequencies to support simultaneous oscillation at such frequencies and an equalizing network with amplitude and phase characteristics versus frequency to support the simultaneous modes of oscillation. The single loop oscillator permits separate control of the two simultaneous different frequencies of oscillation. In order to minimize thermal hysteresis, at least the active portion of the feedback loop does not include inductors. In some applications, the multimode oscillator may include one or more rejection networks to suppress unwanted oscillations. The useful outputs of the multimode oscillator are one or more of the operating frequencies, harmonics and intermodulation products.

Abstract: The invention relates to a temperature-stable transistorised tuned-circuit oscillator. Provided for the purpose of temperature stabilisation of the tuned-circuit voltage is a transistor T2, which is thermally coupled to the tuned-circuit coil L and controls a current source Q in the circuit of the oscillator L, C1, T1, in such a way that temperature-induced variations of the data of the tuned-circuit coil L are compensated.

Abstract: A FET oscillator with increased frequency stability. This is accomplished by using a controlled voltage supply to power the amplifier stage of the oscillator. This voltage changes as the FET amplifier temperature increases in order to reduce the variation in frequency, caused by the amplifier's gain and phase shift changes. By using this compensated amplifier as the active section of an oscillator, the oscillator frequency stability is increased.

Abstract: Certain operational characteristics of a crystal (104) are measured during a testing and grading process. Once determined, information representing these operational characteristics are stored in memory (120) and utilized by a controller (122) to increment a phase increment register (114) upon determining the crystals ambient temperature via a temperature sensing circuit (124). The value stored in the phase increment register (114) is then sent to a phase accumulator (116) where successive phase increments are summed together. This summed value is in turn sent to a sine lookup table (118) where the instantaneous phase value is converted into sine amplitude. Finally, a digital to analog converter (126) converts the amplitude bit stream into an analog signal for use as a reference oscillator frequency having extremely high frequency resolution.

Abstract: A first control circuit is provided with a temperature detector and a memory in which temperature related control data is stored. The control circuit outputs a control signal, which varies with ambient temperature, to a local oscillator which is connected with a mixer. The mixer receives an incoming radio frequency signal and a local frequency signal from the local oscillator and outputs an IF signal. The local oscillator is controlled in a manner wherein the frequency of the IF signal parallels the temperature dependent shift in center frequency of a surface acoustic wave type IF filter. The IF signal is applied to a second mixer to which a second control circuit is coupled. The second control circuit maintains the output of the second mixer at a predetermined value to compensate for the first IF's frequency shift caused by the first control circuit.

Abstract: A crystal oscillator for generating an output oscillation whose frequency is maintained constant independently of the variation of temperature including a first quartz vibrator arranged in a heating unit which includes a thermostat and vibrating at a fundamental frequency, a second quartz vibrator arranged also in the same heating unit and vibrating at a third overtone frequency, a frequency multiplying circuit for multiplying the fundamental frequency by three, a frequency comparator for comparing the fundamental frequency multiplied by three with the third overtone frequency to derive a frequency difference which represents a temperature of the thermostat, and a temperature controlling circuit for controlling the temperature setting of the thermostat in accordance with the detected frequency difference. Any one or both of the fundamental and third overtone oscillations may be derived as an output oscillation.

Abstract: An improved ring oscillator is disclosed which can be formed in a semiconductor substrate. The ring oscillator includes inverters cascaded in a ring-like manner, and a diffused resistor R1 having a positive temperature coefficient and a polysilicon resistor R2 having a negative temperature coefficient for determining bias currents supplied to the inverters. The oscillation frequency tends to decrease with a rise of ambient temperature based on a temperature characteristic of diffused resistor R1 and a temperature characteristic of the oscillator circuit itself; however, the change of oscillation frequency is compensated by a temperature characteristic of polysilicon resistor R2. Therefore, a reference clock signal generating circuit having an oscillation frequency which is not affected by change of the ambient temperature can be formed in the semiconductor substrate.

Abstract: A frequency source (1) in, for example, a remote unit in a mobile communications system, is controlled to maintain a stable frequency signal. In normal operation, the frequency source (1) is frequency locked to an external reference frequency (10). A temperature detecting device (2) monitors the temperature of the frequency source, and information relating to temperature is stored in a storage device (7) together with information relating to control signals (6) applied to the frequency source (1). In the absence of the reference frequency (10), the temperature of the frequency source (1) is detected and the stored information is used to generate a control signal (6) to control the output frequency of the frequency source (1) in accordance with the detected temperature.

Abstract: A digital temperture compensation oscillator for digitally compensating a variation in oscillation frequency due to temperatures, by applying a compensation voltage to a voltage controlled oscillator, comprises temperature detection means, A/D conversion means, memory means, operation means and D/A conversion means. The temperature detection means detects temperatures when the voltage controlled oscillator is operated, and generates a temperature signal. The A/D conversion means receives the temperature signal, digitizes the temperature signal, and generates digital temperature data. The memory means stores compensation data corresponding to the compensation voltage as difference data at corresponding addresses. The difference data includes, when N-stage level difference data (N=a positive integer) are utilized, predetermined reference values of 0th difference data to (N-1)-th difference data of the compensation data and all N-th difference data.

Abstract: There are provided a memory for storing data for calculation of approximate temperature compensation data for the address data outside the temperature compensation range; a discriminator for discriminating whether the address data corresponding to the output from a temperature detector is within the temperature compensation range; a latch circuit for latching the data for calculation of approximate temperature compensation data at the start of operation; a calculator for calculating the approximate temperature compensation data in accordance with the latched data and the address data. The approximate temperature compensation data calculated by the calculator is output as a temperature compensation data when the discriminator discriminates that the address data is outside the temperature compensation range, and D/A converted the temperature compensation. The converted output is used as an oscillation frequency control voltage of the crystal oscillator.

Abstract: A multimode oscillator is disclosed which employs a single gain feedback loop for exciting at least two modes of a resonator to cause the oscillator to oscillate simultaneously at at least two frequencies. The multi-mode oscillator comprises the resonator, an amplifier to provide gain at the appropriate operating frequencies to support simultaneous oscillation at such frequencies and an equalizing network with amplitude and phase characteristics versus frequency to support the simultaneous modes of oscillation. The single loop oscillator permits separate control of the two simultaneous different frequencies of oscillation. In order to minimize thermal hysteresis, at least the active portion of the feedback loop does not include inductors. In some applications, the multimode oscillator may include one or more rejection networks to suppress unwanted oscillations. The useful outputs of the multimode oscillator are one or more of the operating frequencies, harmonics and intermodulation products.

Abstract: An oscillation circuit has a differential amplifier including a constant current source formed by a resistor and a transistor whose emitter is grounded through the resistor, and a feedback circuit through which an output of the differential amplifier is positively fed back to an input of the same differential amplifier. The oscillation circuit further includes a band-gap regulator for producing a band-gap voltage proportional to a thermal voltage of transistors forming the band-gap regulator whose emitter areas are different with each other, and an operational amplifier for DC-amplifying the band-gap voltage and applying the amplified band-gap voltage to the base of the transistor forming the constant current source. The oscillation circuit is capable of performing a stable oscillation against a wide range of temperature changes.

Abstract: A crystal resonator with plural electrodes comprises a crystal piece, first, second and third pairs of electrodes. The crystal piece causes shear vibration. The first electrode pair is provided in the center of the crystal piece and coupled to a variable impedance. The second and third electrode pairs are provided on both sides of the first electrode pair. The second and third electrode pairs are electrically connected together and are coupled to an oscillation 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 digitally compensated modulation system for frequency synthesizers has a single modulation input line with flat frequency response to zero hertz. The above is accomplished while eliminating circuit components and adjustments by integrating reference oscillator temperature compensation, modulation compensation for changes in the voltage controlled oscillator modulation sensitivity and modulation compensation for changes in the reference oscillator modulation sensitivity. Signals requiring modulation enter a microprocessor and are summed together with a microprocessor generated signal and a temperature compensation input to create a composite modulation signal. The composite modulation signal is then multiplied by appropriate constants and sent to the synthesizer.

Abstract: A variable capacitance circuit comprising a capacitor array, associated switching elements and transient impedance varying circuits. The capacitor array comprises a plurality of capacitor elements connected to a common node coupled to a crystal oscillator in a crystal oscillator portion and each capacitor element includes a connected switching element that controls activation of selected capacitor elements that are selectively placed in operation as load capacitance with the crystal oscillator to change and adjust its frequency. Further, circuits are provided in a temperature compensation portion to selectively control the activation of the switching elements based upon decoded compensating values provided in memory, such as based upon sensed oscillator temperature conditions.

Abstract: An RF oscillator is disclosed that can be tuned to operate over a wide range of frequencies while maintaining advantageous bias conditions. The oscillator includes circuitry that adjusts an oscillator bias signal in response to changes in oscillator frequency and/or ambient temperature, and does so without resort to using the same signal for both bias and frequency control. By so doing to control parameters such as phase noise, output power and compression angle, both the frequency range and temperature range of an oscillator can be extended, while simultaneously improving the oscillator's performance.

Abstract: A digital temperature-compensated oscillator comprises a crystal oscillator, a first memory previously storing digital temperature compensation data obtained by previously measuring the relation between the ambient temperatures and the frequency deviations of the crystal oscillator, a second memory for storing frequency offset amounts of the oscillation frequency of the crystal oscillator, a temperature sensor for outputting analog detection data relating to the ambient temperature, an A/D converter for converting the analog detection data to digital detection data, a readout circuit for reading out temperature compensation data corresponding to the digital detection data and stored in the first memory according to the digital detection data and reading out the frequency offset amount stored in the second memory according to the digital detection data, an operation circuit for effecting the following calculation by use of the readout temperature compensation data and readout frequency offset amount to derive

Abstract: A compensation circuit (14) for a ring oscillator (12) having an odd plurality of series-connected CMOS inverter stages includes first and second P-channel transistors and a resistor. The first transistor (32) has a source coupled to VDD and a gate coupled to ground. The resistor (34) is coupled between the drain of the first transistor and ground. The second transistor (36) has a source coupled to VDD, a gate coupled to the drain of the first transistor, and a drain coupled to a supply node of each of the inverter stages of the ring oscillator for providing a supply voltage that is compensated with respect to voltage, temperature, and semiconductor processing variables. In operation, the conductivity of the first transistor inversely controls the conductivity of the second transistor that supplies a compensated power to the inverter stages. The compensated power controls the conductivity of the transistors in the ring oscillator and the corresponding frequency of oscillation.

Abstract: A pulse repetition frequency (PRF) pushing compensation circuit to negate PRF-induced frequency shifts and ambient temperature change-induced frequency shifts in pulsed RF sources. The PRF pushing compensation circuit samples PRF voltage and feeds it into a resistor-capacitor (RC) network so that the DC voltage component across the capacitor is directly proportional to the PRF. The DC voltage is then amplified, via a transistor, and fed to a varactor diode circuit coupled to the source's frequency determining element (e.g., dielectric resonator, microwave cavity, or other element). With a varactor diode tuning the source, the capacitor voltage derived from the PRF voltage is applied to the varactor diode to effect a frequency shift in the pulsed RF source which is equal and off-setting to the PRF-induced frequency shift. Temperature sensitive resistors can be used in the DC offset voltage of the varactor diode circuit to compensate for frequency changes due to ambient temperature variances.

Abstract: The invention relates to a temperature-stable inductive proximity switch having a transistorized resonant circuit oscillator. The feeding into the emitter-to-collector circuit of the resonant circuit transistor T1 of a balancing current, which depends on the individually determined temperature of the resonant circuit transistor T1 and the individually determined temperature of the resonant circuit coil, ensures that the proximity switch is temperature-stable with respect to its switching distance for every adjusted basic current.

Abstract: A crystal reference frequency is characterized by determining the compensation signal variations of a compensation signal over temperature for corresponding signal characterization words. The frequency shift variations of the crystal over temperature are determined and the temperature at which the inflection point of the crystal occurs is found. An inflection point characterization word is found which matches the temperature at which the inflection point of the crystal occurs to the temperature at which the inflection point of the compensation signal occurs. The frequency variations of the crystal are correlated to the compensation signal variations and a signal characterization word is selected which substantially minimizes the frequency variations of the crystal over temperature.

Abstract: A temperature controlled crystal oscillator circuit comprising an amplifier (12) having a feedback path including a crystal (26) and a frequency pulling element (28), and a temperature compensating voltage generating circuit (30) coupled to the frequency pulling element (28). The voltage generating circuit (30) produces a voltage, V.sub.comp, generated in accordance with the following function:V.sub.comp =b*exp[a1(T-T.sub.R)]+b*exp[-a2*(T-T.sub.R)]+c*(T-T.sub.R)whereT.sub.R is a reference temperature in degrees KelvinT is the working temperature in degrees Kelvina1, a2, b and c are constants.

Abstract: A device utilizing a quartz crystal resonator with an orientation substantially equal to 21.93.degree./34.10.degree.. The crystal resonator is capable of vibrating simultaneously in two thickness modes, namely the B-mode and the C-mode. Because of the nature of the difference between the B- and C-modes, the B-mode may be used as an indication of the resonator temperature in order to compensate the C-mode frequency signal. A digital technique for temperature compensation by using the crystal itself as a sensor and a feedback loop varies the heater on the surface of the crystal. The temperature sensor compensation system contains a quartz resonator with a heater affixed thereon. The resonator is arranged as part of the oscillator to generate both B-mode and C-mode frequency signals. The C-mode signal is used as a time standard or frequency reference. Initially, the frequency of the B-mode is counted. The count is started at the same time the frequency count of the C-mode is initiated.

Abstract: A temperature-compensated quartz crystal oscillator has two or more temperature compensating units. The first temperature compensating unit compensates the frequency-temperature characteristics of the oscillator over its rated temperature range. The other temperature compensating units further independently compensate the frequency-temperature characteristics of the oscillator within respective specific temperature regions of the compensated frequency-temperature characteristics to obtain desired frequency-temperature characteristics for the crystal oscillator.