Abstract: A temperature compensation technique is disclosed which allows to obtain a compensated clock signal. The temperature compensation technique comprises the use of a thermal model of the oscillator with a temperature sensor in order to accurately compute the oscillator frequency, irrespective of time-variations and rates.

Abstract: A bias current IB additionally provided to a current-controlled circuit 13 in a PLL circuit is the sum of bias currents IB1 and IB2 which are generated by a bias adjustment circuit (18, 19, 20, 21 and 22) and a bias current generating circuit (23 and 24), respectively. The bias adjustment circuit adjusts the bias current IB1 in response to an adjustment start signal ADJ such that a control voltage VC converges to a reference voltage VREF, and ceases the adjustment when the convergence has been achieved. The reference voltage VREF is determined to be a value at an almost middle point in a range of the variable VC in the PLL circuit. The bias current generating circuit has a circuit 23 generating a bias voltage VT and a circuit 24 converting the VT into a current IB2, wherein the temperature characteristic of the bias voltage VT is reverse to that of the control voltage VC under the condition that the frequency of an oscillation signal OCLK is fixed.

Abstract: An oscillator circuit having a charge storage device, an upward integration current source, and a downward integration current source is described. The charge storage device is also connected to a comparator in order to drive the current sources as a function of a lower comparator threshold and an upper comparator threshold. In consequence, a triangular waveform voltage is formed across the charge storage device, on the basis of the relaxation principle. The difference voltage from the two comparator thresholds is dropped across a first resistor. Since the comparator itself as well as the lower and upper current thresholds are formed in a common current path, this oscillator circuit has a particularly low current draw.

Abstract: An improved temperature compensated quartz oscillator, which includes a package for mounting compensating circuitry over a cavity instead of on a planar layer, reduces the chip failure rate by preventing undesired contact of the compensation circuitry with the material forming the layer upon which the circuitry is mounted.

Abstract: A clock system is disclosed which includes a dual mode oscillator crystal having a first output having a frequency related to a temperature of the oscillator crystal and a second output having a frequency substantially stable with respect to temperature. The clock includes a temperature maintenance device. The temperature maintenance device and the oscillator crystal are disposed in a thermally insulated chamber. The clock includes a processor operatively coupled to the temperature maintenance device and the oscillator crystal. The processor is adapted to operate the temperature maintenance device so as to maintain a temperature of the chamber within a predetermined range. The processor is adapted to calculate a substantially constant frequency clock signal from the second output and a ratio of the frequency of the first output with respect to the frequency of the second output.

Abstract: A frequency-adjustable oscillator suitable for digital signal clock synchronization comprises a crystal oscillator circuit for generating a driving signal and having a voltage-variable control input for adjusting a frequency of the driving signal, a phase detector circuit for generating a phase offset signal, a filter which operates on the phase offset signal to produce a VCO control signal, a voltage controlled oscillator circuit operably linked to the filter and responsive to the VCO control signal for generating an analog controlled-frequency signal, a frequency divider circuit for generating a reduced frequency feedback signal in response to the controlled-frequency signal. The frequency-adjustable oscillator also includes a double-sided package including a platform having a central portion and an outer portion with sidewalls extending substantially upwardly and substantially downwardly from the outer portion of the platform.

Abstract: A self refresh circuit for a semiconductor memory device can reduce power consumption by varying a self refresh period according to a data holding time of a cell varied by a temperature. The self refresh circuit includes a temperature sensing unit for sensing a temperature, and generating a bias current for adjusting a self refresh period according to a data holding time of a memory cell varied by the temperature, and a ring oscillator unit for generating a pulse signal having a period actively varied according to the temperature by the bias current from the temperature sensing unit.

Abstract: A temperature compensated crystal oscillator is disclosed, which comprises a crystal package including a package board and a crystal oscillating piece, conductive patterns for constituting a temperature compensating circuit formed on a surface of the package board, exterior terminals formed at corners of the board, temperature compensating components formed on the surface of the board, and resin molded part enveloping the surface of the board. With a lower surface of a crystal package serving as a component mounting area, it is not necessary to provide an additional printed circuit board required for mounting of temperature compensating components, and it is possible to provide a compact TCXO having a surface area corresponding to that of a crystal package.

Abstract: A method and apparatus are provided for constructing a temperature controlled crystal oscillator chip. The method includes the steps of disposing a connection pad on a surface of the chip, providing a first circuit within the chip for control of a first chip function through a first interconnection with the connection pad and providing a second circuit within the chip for control of a second chip function, unrelated to the first chip function, through a second interconnection with the connection pad.

Abstract: This invention provides a voltage controlled oscillator that improves the linearity of frequency variable characteristics and increases the range of frequency that can be varied by a control voltage. A resistor circuit is connected between a piezoelectric resonator X and an oscillator circuit. The resistor circuit includes a plurality of oscillation-amplitude adjusting resistors Rs1 to Rsn and corresponding switches SW1 to SWn. The resistor circuit adjusts the amplitude of oscillation. When a control voltage Vc applied to a varactor Cv is at a low potential, clipping by a forward voltage of the varactor Cv is suppressed, and the frequency is linearly changed by the control voltage Vc within a range of a low potential to a high potential.

Abstract: Disclosed herein is a temperature compensated crystal oscillator and method for adjusting an output frequency thereof. The temperature compensated crystal oscillator has a crystal oscillating unit and at least one part for temperature compensation and oscillation circuits. The temperature compensated crystal oscillator has a layered structure and a planar thin film resistor. The layered structure has an upper layer on which the crystal oscillator and the part are mounted, and at least one layer on which conduction patterns fare formed. The planar thin film resistor is arranged on an upper surface of a bottom layer of the layered structure so as to adjust an output frequency of the temperature compensated crystal oscillator. Therefore, an area occupied by a resistor for adjusting an output frequency can be minimized by inserting a resistor for adjusting an output frequency between layers, thus miniaturizing products.

Abstract: Disclosed herein is a temperature compensated crystal oscillator. The temperature compensated crystal oscillator has first and second layered structures, an IC chip, a crystal vibrating chip, a resin mold portion and a metal cover. The first layered structure is comprised of at least one layer and provided with a cavity formed therein. The second layered structure is arranged on the upper surface of the first layered structure, comprised of at least one layer, and provided with a cavity formed in a region not overlapped with the cavity of the first layered structure. The IC chip is inserted into the cavity of the first layered structure. The crystal vibrating chip is inserted into the cavity of the second layered structure. The resin mold portion is formed by charging resin into the cavity of the first layered structure accommodating the IC chip to form its bottom surface level with the lower surface of the first layered structure.

Abstract: An oscillator assembly has a voltage controlled crystal oscillator that produces a stable reference frequency. The voltage controlled crystal oscillator is connected to an electronic frequency adjust voltage. A temperature compensation circuit is connected to the voltage controlled crystal oscillator. The temperature compensation circuit provides a temperature compensation voltage to the voltage controlled crystal oscillator. A trim effect compensation circuit is connected between the temperature compensation circuit and the electronic frequency adjust voltage. The trim effect compensation circuit adjusts the temperature compensation voltage in response to a change in the electronic frequency adjust voltage.

Abstract: An oscillator assembly has a voltage controlled crystal oscillator that produces a stable reference frequency. The voltage controlled crystal oscillator is connected to an electronic frequency adjust voltage. A temperature compensation circuit is connected to the voltage controlled crystal oscillator. The temperature compensation circuit provides a temperature compensation voltage to the voltage controlled crystal oscillator. A trim effect compensation circuit is connected between the temperature compensation circuit and the electronic frequency adjust voltage. The trim effect compensation circuit adjusts the temperature compensation voltage in response to a change in the electronic frequency adjust voltage.

Abstract: By supplying a control voltage that corresponds to the phase difference between an output signal of a temperature-compensated crystal oscillator (TCXO 1) and a signal obtained by dividing an output signal of a voltage-controlled SAW oscillator (VCSO 4) using the SAW resonator to the VCSO 4, the frequency of the output signal of the VCSO 4 is controlled so as to be constant over a wide temperature range.

Abstract: A voltage controlled crystal oscillator (VCXO), for example, as used in a mobile communications terminal, has its output frequency Fref stabilised against temperature drift using frequency correction information received, for example, in a downlink signal from a base station. A controller uses the frequency correction information to produce a digital value which is supplied to a DAC which controls the output frequency of the VCXO. While the frequency is being stabilised in this manner, compensation values are determined based on the DAC value and temperature values from a temperature ADC, and stored in memory. When the correction information ceases to be available, the compensation values from the memory are used to compensate for temperature fluctuations. Each compensation value corresponds to a linear temperature region, and relates to the gradient for that temperature region.

Abstract: A frequency controlled oscillator (100) is manufactured using an array (200) of mechanically interconnected oscillator bases (110) having component cavities (130) and wiring patterns therein. A frequency control component (120) serves as a cover for a cavity within the array, and in addition is electrically connected to oscillator components (140, 150) mounted within the cavity to regulate the frequency of electrical oscillation. Both the oscillator bases and finished oscillators may be tested while still in the array, prior to being separated from each other. In a most preferred embodiment, the array of oscillator bases are manufactured from a polymeric sheet material laminated with electrically conductive traces. The polymeric sheet material is selectively punched or formed prior to lamination so that intermediate and upper layers (112, 113) have predetermined sections removed.

Abstract: A PLL-controlled oscillator that can be suitably used for such purposes as a jitter filter in an optical transmission system includes an input voltage-switching control oscillator as a voltage-controlled oscillator (VCO). The input voltage-switching control oscillator includes: an oscillation closed loop that is provided with a variable-voltage capacitance element; and a switch for interchangeably selecting one of a plurality of voltages in accordance with a selection signal and applying the selected voltage as a control voltage to the variable-voltage capacitance element.

Abstract: A temperature-compensated crystal oscillator is provided with an IC (integrated circuit) having a power supply terminal, an output terminal, and an automatic frequency control (AFC) voltage input terminal. In the temperature-compensated crystal oscillator, at least one oscillation circuit is integrated and the frequency-temperature characteristic of a quartz crystal unit is compensated. The temperature-compensated crystal oscillator includes one or more damping resistors for reducing the resonance acuteness of parasitic resonance circuits which result from inductance produced when mounting the IC on a wiring board and stray capacitance existing in the vicinity of each terminal of the IC. The dumping resistors are connected to at least one of the power supply terminal, output terminal, and automatic frequency control voltage input terminal.

Abstract: A temperature compensated oscillator keeping the area of a capacitor array and the bit number of a memory from increasing and allowing for high precision is provided. A adjusting method of such a resonator and an integrated circuit for temperature compensated oscillation are also provided. A capacitor array and a variable capacitance diode are connected and used as a load capacitance in an oscillation circuit, and the capacitance value of the former is digital-controlled and that of the latter is analog-controlled, so that the amount of compensation data necessary for the digital control is reduced and highly precise temperature compensation is permitted.

Abstract: A high-frequency oscillation circuit includes a resonance circuit and an active circuit. The active circuit includes a field-effect transistor and a capacitor. An impedance-conversion circuit including a high-impedance line, a capacitive stub, and a connecting line such as wire, is connected between the active circuit and the resonance circuit. Accordingly, the impedance-conversion circuit can convert the characteristic impedance of the resonance circuit so that the absolute value of the reflection coefficient of the active circuit increases. As a result, the oscillation conditions can be easily fulfilled.

Abstract: An integrated frequency source with an integrated frequency standard and an integrated frequency synthesizer is disclosed. A voltage-controlled oscillator in the frequency standard is eliminated with a resulting improvement in phase noise. A reference frequency in the frequency standard is provided directly to the frequency synthesizer. The integrated frequency source is put on frequency over temperature by storing reference frequency errors over temperature in a lookup table, measuring the temperature, and calculating in a microprocessor synthesizer control data that offsets the synthesizer to compensate for reference frequency errors.

Abstract: A clock oscillator embedded in an integrated circuit, including a piezoelectric resonator formed on the integrated circuit; a clock generator coupled to the on-chip piezoelectric resonator, one or more sensors adapted to sense one or more environmental parameters affecting the piezoelectric resonator; and a processor coupled to the clock generator and the one or more sensors to adjust the frequency of the clock generator based on the one or more environmental parameters.

Abstract: A pseudo-cubic function generator circuit comprises a CMOS inverter which is applied with a detected voltage of a sensor and supplied with a power supply voltage, and a voltage divider circuit for dividing the power supply voltage, wherein an output terminal of the CMOS inverter is connected to a voltage division point of the voltage divider circuit to generate an output voltage from the voltage division point. The pseudo-cubic function generator circuit can directly generate a large voltage change in a simple circuit configuration with a reduced noise component, and facilitates a setting of each parameter for specifying a cubic function curve. The parameter is set, for example, by scaling substantial gate areas of a P-MOS FET and an N-MOS FET which constitutes the CMOS inverter.

Abstract: A system and method for clock recovery from an input data stream recovers the clock signal in a manner that preserves the signal strength of the input signal. The measure of signal strength, referred to herein as the “signal strength indicator” is in turn used to normalize the output of a phase detector in a phaselocked loop (PLL), and the normalized signal is used as an input to the PLL oscillator to recover the clock signal from the input data signal. In this manner, the phaselocked loop is used to perform narrow band filtering, while baseband amplifiers are used to compensate for reference signal power variations. In one aspect, the present invention is directed to a clock recovery system for recovering a clock signal from an input data signal. The system comprises a primary phase detector for receiving an input data signal, and for combining the input data signal with a feedback signal to generate a phase difference signal.

Abstract: An apparatus compensates for voltage and temperature variations on an integrated circuit with: a voltage sensor having a digital voltage output; a temperature sensor having a digital temperature output; a register coupled to the voltage sensor and the temperature sensor, the register adapted to concatenate the digital voltage output and the temperature output into an address output; and a memory device having an address input coupled to the address output of the register, the memory device being adapted to store one or more corrective vectors.

Abstract: The invention relates to a method of controlling the operation of a voltage controlled oscillator (VCO) with respect to a SAW filter (6) within a broadcast data receiver (BDR) (104). Over time, it is found that during normal operation of the BDR (104), the SAW filter (6) is susceptible to frequency drift which can affect the operation of the BDR. In accordance with the invention, temperature readings are taken at various time intervals from within the BDR (104) to provide an indication of changes in temperature over time and, if the temperature does change in the BDR with time then the operating frequency of the VCO can be adjusted to a predefined frequency value which is appropriate for the temperature values measured. By adjusting the operating frequency of the VCO with changes in temperature, the drift of the SAW filter (6) can be compensated for, thereby ensuring the continued operation of the BDR (104) in the required manner.

Abstract: An oscillator includes an oscillator circuit that receives a control signal having a signal level. The oscillator circuit generates an oscillator signal having a frequency that is proportional to the signal level and that is within a frequency range. A compensation circuit stabilizes the oscillator circuit such that the frequency range includes first and second predetermined frequencies. Thus, such an oscillator can be used to generate an oscillator signal having a first frequency in one application and having a second frequency in another application. The compensation circuit stabilizes the frequency range of the oscillator signal so that it includes the first and second frequencies over broad ranges of operating conditions such as temperature and supply voltage and over broad ranges of component characteristics such as gate dielectric thickness.

Abstract: The invention relates to a device and a method for temperature compensation via the determination of cut-angles of a master and a slave crystal (mc, sc) employed in a master and slave oscillator (m, s). When the master and the slave oscillator (m, s) have been tuned to their center frequencies (fc_m, fc_s), then the temperature characteristic of the slave oscillator (s) is actively detuned with respect to the temperature characteristic of the master oscillator (m). In a detuned state a frequency ratio parameter (n_s) of the slave to the master output frequency (f_s/f_m) is determined and the cut-angle is determined by using this parameter (n_s) to read out the cut-angle dependent on the temperature (T) from a memory (MEM). The invention also relates to a temperature compensation device and method where two crystals of different cut-angles are used and a frequency ratio parameter is determined to determine the identity/symmetry or difference of the cut-angles.

Abstract: The frequency error of an oscillator is minimized by characterizing the operating environment of the oscillator. An electronic device monitors parameters that are determined to have an effect on the frequency accuracy of the internal frequency source. Temperature is one parameter known to have an effect on the frequency of the internal frequency source and a primary contributor to device temperature is the RF Power Amplifier (PA). The electronic device collects and stores the activity level of the PA. The effective PA duty cycle over a predetermined period of time is calculated. The LO operating environment is stabilized by operating the PA at the calculated duty cycle when the LO is required to operate in a high stability mode.

Abstract: A method and apparatus is directed to generating an oscillation frequency utilizing the thermal heat transfer properties of semiconductor material as a feedback loop in an oscillator. The oscillator includes a comparator that compares two input signals and enables one of two heater circuits. Each heater circuit is thermally coupled to a sensor and reference circuit. Each sensor and reference circuit pair is arranged such that the reference circuit is heated while the sensor cools. The combination of each sensor and reference circuit produces input signals for the comparator. The frequency of the oscillator is determined by the heat transfer rate between the heater circuit and the corresponding sensor, and the thermal cooling rate of the other sensor. Changing the biasing currents, and distances between the heat sources and the thermal sensors adjust the duty cycle and frequency.

Abstract: A temperature compensated oscillator has a frequency comparing circuit for comparing a frequency of an oscillating output signal of an oscillator circuit and a frequency of an external reference frequency signal externally inputted, and also has a sequential comparing register for determining each bit of a compensation datum based on this comparison. A digital signal from the sequential comparing register is applied to an input of a D/A converter for generating a control voltage of a varicap diode. The temperature compensated oscillator performs a self compensating operation for sequentially determining each bit of the sequential comparing register every frequency comparison, and conforming the frequency of the oscillating output signal to that of, the external reference frequency signal. The digital signal from the sequential comparing register is stored as compensating data corresponding to a detecting temperature of a temperature detector at that time.

Abstract: An oscillator circuit configured to generate an output signal having a frequency comprising a current source, a trim circuit, and one or more capacitors. The current source may be configured to generate a temperature independent current in response to a first adjustment signal. The trim circuit may be configured to generate the first adjustment signal. The one or more capacitors may be configured to charge to a controlled voltage using the temperature independent current. The controlled voltage may regulate a variation of the frequency of the output signal.

Abstract: A frequency-adjustable oscillator suitable for digital signal clock synchronization comprises a crystal oscillator circuit for generating a driving signal and having a voltage-variable control input for adjusting a frequency of the driving signal, a phase detector circuit for generating a phase offset signal, a filter which operates on the phase offset signal to produce a VCO control signal, a voltage controlled oscillator circuit operably linked to the filter and responsive to the VCO control signal for generating an analog controlled-frequency signal, a frequency divider circuit for generating a reduced frequency feedback signal in response to the controlled-frequency signal, and a sinewave-to-logic level translator circuit for generating a digital output signal having substantially the same frequency as the controlled-frequency signal. The crystal oscillator circuit includes a discrete varactor responsive to the control input and a fundamental mode AT-cut quartz resonator.

Abstract: The temperature of an oscillation circuit (47) is detected by a temperature detection circuit (13), a cubic term voltage generation circuit of a control voltage generation circuit (23) generates a cubic term voltage as a control voltage based on an output voltage of the temperature detection circuit (13), and a frequency adjustment circuit (45) changes an oscillation frequency of the oscillation circuit (47) by the control voltage.

Abstract: Based on an initial crystal coefficient value, a processor generates a control signal for a frequency synthesizer. The processor estimates a new crystal coeficient value based on a comparison of the frequency of the output of the frequency synthesizer against a target output frequency in relation to a crystal temperature value.

Abstract: Clock generation circuits for an integrated circuit device are provided including a temperature sensor circuit, the temperatures sensor circuit including a calibration circuit responsive to a temperature coding signal and a temperature sensor. The temperature sensor circuit has a first or test mode state in which a temperature output signal of the temperature sensor circuit is based on a temperature sensor output control signal and a second or normal operating mode state in which the temperature output signal is based on the temperature sensor and the calibration circuit. A clock period controller circuit includes a calibration circuit responsive to a period coding signal. The clock period controller circuit generates a period control signal based on the temperature output signal and the calibration circuit of the clock period controller circuit. A clock generator circuit generates a clock signal based on the period control signal.

Abstract: A variable-frequency digital ring oscillator provides small and consistent frequency adjustments throughout a locked range. The ring oscillator of the invention is standard cell placeable and operates at the technology limits to provide small and precise delay changes that is inexpensive to implement. The digital variable-frequency ring oscillator includes multiple macro delay elements forming an inverter ring circuit, each element having an individual macro delay unit that in turn is comprised of multiple adjustable delay units. All of these adjustable delay units are controlled by a single delay control signal.

Abstract: A temperature compensated crystal oscillation circuit adapted to be contained within a small device package and providing an output frequency accuracy of approximately +/−2 ppm over a temperature range or less than 2 minutes per year over the temperature range. The device includes crystal and a single integrated circuit wherein the integrated circuit has a temperature sensing circuit with a digital output, control circuitry, a memory circuit and a switched capacitor array for compensating the oscillation of the crystal oscillator over temperature.

Abstract: An oscillating circuit (10) includes a quartz crystal oscillator (12) for generating a clock signal (20). The clock signal is synchronized to a master signal (19) during the lock-in periods when the oscillating circuit (10) has access to the master signal (19). During the holdover periods when the oscillating circuit (10) loses access to the master signal (19), an oscillation frequency function predicts the crystal oscillation frequency in terms the physical parameters, e.g., time and temperature, that may affect the crystal oscillation frequency. The predicted frequency is compared with a standard frequency to generate an error signal. In response to the error signal, a fraction handler block (28) determines whether adding cycles to or deleting cycles from the clock signal, thereby calibrating the oscillation signal (13) of the oscillating circuit (10).

Abstract: A micropower RC oscillator having stable frequency characteristics with varying temperature includes a number of inverting circuits which are driven by an external driving voltage and connected in series with each other and an RC circuit having a resistor disposed in between a head-inverter and a tail inverter to form a closed loop and a capacitor disposed between the tail-inverter and the head-inverter. The resistor comprises a plurality of unit resistors constituting of a P+ diffusion resistor and a polysilicon resistor having opposing characteristics with respect to temperature variation at a predetermined ratio. A resistance regulator controls the resistance of the resistor by decoding an external resistance setting data to select a unit resistor that determines the oscillation frequency effectively.

Abstract: In a hermetically sealed container constituted by a lid (105), frame (103), and substrate (104), a piezoelectric vibrator (101) is fixed on the substrate (104) (on the upper surface of the substrate) with fixing members (104a) made of a conductive material, and a semiconductor component (102) is flip-chip mounted on the lower surface of the substrate (104).

Abstract: A dual-cavity temperature compensated crystal oscillator (100) provides a three-layer ceramic package (110), with a crystal (170) sealed in a well or cavity (148). Oscillator components (180-184) such as a compensation circuit and an oscillator are attached through screened solder onto the back side of the ceramic package (110) and are encapsulated within potting compound or encapsulant. Electrical connection is provided between the oscillator and compensation circuitry and the piezoelectric element (170) to produce a frequency-controlled oscillator. After frequency tuning, a hermetic seal is provided between a cover (160) and ledge (140) to hermetically seal the cavity (148).

Abstract: A clock system is disclosed which includes a dual mode oscillator crystal having a first output having a frequency related to a temperature of the oscillator crystal and a second output having a frequency substantially stable with respect to temperature. The clock includes a temperature maintenance device. The temperature maintenance device and the oscillator crystal are disposed in a thermally insulated chamber. The clock includes a processor operatively coupled to the temperature maintenance device and the oscillator crystal. The processor is adapted to operate the temperature maintenance device so as to maintain a temperature of the chamber within a predetermined range. The processor is adapted to calculate a substantially constant frequency clock signal from the second output and a ratio of the frequency of the first output with respect to the frequency of the second output.

Abstract: The invention relates to phase and frequency-locked loop circuits (PLL and FLL circuits) with a controllable tracking oscillator whose signal phase relationship or frequency, respectively, is influenced by an external parameter, a reference oscillator, as well as a phase or frequency comparator, the output signal of which is used to control the tracking oscillator in such a way that any phase or frequency errors are reduced. The invention provides for an element for the measurement of the external parameter (such as a microprocessor) which is capable of receiving a signal representing the output signal of the phase or frequency comparator, and convert it into a measurement value that represents the present value of the external parameter. This external parameter can, for example, represent the ambient temperature or the supply voltage of the tracking oscillator.

Abstract: An explanation is given of a circuit arrangement for generating the control potential for a field-effect transistor from the output voltage (VA) of a filter circuit (20). In order to reduce the noise component thereof, the output terminal (A) of the filter circuit (20) is connected to a capacitive voltage divider (C1, C2), the tap of which carries the control potential. It is possible to control the charge state of the voltage divider (C1, C2) for the purpose of setting a predetermined potential value at the tap (10).

Abstract: A method and apparatus are provided for exchanging data with a temperature controlled crystal oscillator chip. The method includes the steps of receiving data within the temperature controlled crystal oscillator chip through a first bonding pad of the chip during a first time interval and transmitting data from the temperature controlled crystal oscillator chip through the first bonding pad of the chip during a second time interval.

Abstract: A crystal oscillator according to the present invention prevents abnormal oscillation at a temperature in a low-temperature area equal to or lower than an ordinary temperature. The crystal oscillator is configured such that a crystal vibrator is made to abut against a heat source, and the temperature of the crystal vibrator can be kept higher than a temperature where abnormal oscillation occurs. The temperature of the crystal vibrator is assumed to be, for example, higher than 0° C. Additionally, as the heat source, for example, a power transistor that amplifies an oscillation output is used.

Abstract: A software controlled crystal oscillator employing a method for digitally controlling a reference frequency of an oscillator, the method includes the steps of: locking a first signal produced by a first tunable software oscillator on to a first resonant frequency of a temperature sensing resonator; locking a second signal produced by a second tunable software oscillator on to a second resonant frequency of the temperature sensing resonator; estimating a temperature of the temperature sensing resonator using the first signal and the second signal; estimating the first resonant frequency and the second resonant frequency based upon the temperature; and adjusting the first signal to approximate the estimated first resonant frequency. An additional step includes controlling the reference frequency of the oscillator based upon the first signal such that the reference frequency is compensated for temperature.

Abstract: A dual-cavity temperature compensated crystal oscillator (100) provides a three-layer ceramic package (110), with a crystal (170) sealed in a well or cavity (148). Oscillator components (180-184) such as a compensation circuit and an oscillator are attached through screened solder onto the back side of the ceramic package (110) and are encapsulated within potting compound or encapsulant. Electrical connection is provided between the oscillator and compensation circuitry and the piezoelectric element (170) to produce a frequency-controlled oscillator. After frequency tuning, a hermetic seal is provided between a cover (160) and ledge (140) to hermetically seal the cavity (148).