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 broadband, very low phase noise, temperature stable, sync loss free voltage controlled oscillator (“VCO circuit”) is described. One use of the invention would be in a radio receiver for receiving phase modulated signals from a remote transmitter. In one embodiment of the invention, the VCO circuit is disposed on a printed wiring board (“PWB”) spaced apart from the PWB on which the synthesizer circuit is disposed. The VCO circuit may comprise a resonator, a voltage controlled oscillator, a varactor, and one or more buffer amplifiers. Additionally, a positive temperature coefficient resistive heating element (“PTC”) may be included. In a preferred embodiment, the resonator, voltage controlled oscillator, varactor, and buffer amplifiers may be disposed on one side of the PWB and the PTC may be disposed on the other side of the PWB. Blind vias in the PWB enhance heat transfer from the PTC to the circuit elements on the other side of the PWB.

Abstract: A broadband, very low phase noise, temperature stable, sync loss free voltage controlled oscillator (“VCO circuit”) is described. One use of the invention would be in a radio receiver for receiving phase modulated signals from a remote transmitter.

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: This temperature-compensated crystal oscillator includes: a temperature sensor 11; an analog type temperature compensating section 12; a digital type temperature compensating section 13; an adder circuit 14; and a voltage controlled crystal oscillating circuit 3. The analog type temperature compensating section 12 and the digital type temperature compensating section 13 each generate temperature compensation voltages based on an input voltage corresponding to the temperature detected by the temperature sensor 11. Both of these temperature compensation voltages are added to each other by the adder circuit 14 and the resultant added voltage is applied to a voltage control terminal of the voltage-controlled crystal oscillating circuit 3. Thereby, an oscillation frequency of the voltage-controlled crystal oscillating circuit 3 is stabilized, resulting in realization of the temperature compensation of a crystal resonator 4.

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 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: A precision oven-controlled crystal oscillator (OCXO) uses an adjustment feedback signal that, when mixed with a reference signal from a stable reference oscillator, accurately controls the generation of an output signal from a voltage controlled crystal oscillator (VCXO). An OCXO according to the invention has high stability and high accuracy. The digital OXCO can be manufactured at low cost, and is particularly beneficial for Code Division Multiple Access (CDMA) base station applications in cellular communication networks an the like.

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: 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 controllable crystal oscillator includes a crystal resonator having first and second electrodes, a gain stage having first and second terminals connected to the first and second electrodes for starting and maintaining the oscillation, first and second capacitor banks connected to the first and second terminals for providing a capacitive load to the resonator, and first and second dynamic switches interconnected between the terminals and the respective capacitor banks for cycling the capacitor banks in and out of connection.

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 virtual coherent signal controlled laser oscillator for use in optical phase locked coherent receivers. The present invention employs a fixed laser oscillator in combination with a signal controlled microwave oscillator. A single sideband mixer processes the signals output by the laser oscillator and microwave oscillator to generate a single controlled optical frequency signal.

Abstract: A self-calibrating integrated circuit includes a processor having at least one analog function used with the processor; one or more sensors adapted to sense one or more environmental parameters of the at least one analog function; and a solid state memory being configured to store the one or more environmental parameters of the at least one analog function.

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: 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: A tunable superconductor apparatus or associated method. The apparatus comprises a coil, a first superconductor film portion, a second superconductor film portion, and an actuator. The first superconductor film portion is electrically coupled to the coil. The second superconductor film portion is inductively coupled to the first superconductor film portion. Displacement of the second superconductor film portion relative to the first superconductor film portion changes the capacitance between the second superconductor film portion and the first superconductor film portion. The actuator is capable of relatively displacing the second superconductor film portion and the first superconductor film portion to change a resonant frequency of the tunable superconductor apparatus.

Abstract: An apparatus and method for stabilizing the frequency of a piezoelectric crystal resonator, especially useful in common emergency positioning radio beacons. A temperature compensated crystal oscillator circuit (TCXO) is mounted on one surface of a thin substrate. The TCXO includes a piezoelectric device such as a quartz resonator and a capacitor thermistor compensation network to reduce the frequency fluctuations of the crystal through variations in temperature. A heating circuit is mounted to the opposing surface of the substrate, thereby providing a thermal connection between the two circuits. The heating circuit includes a temperature sensor for sensing changes in ambient temperatures and a heater control amplifier for adjusting the power of a heating element. The substrate with the two circuits disposed thereon is suspended within a hermetically sealed enclosure by a plurality of support pins.

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 space vehicle includes a temperature sensitive oscillator carried by a housing. The temperature sensitive oscillator includes a radiation hardened inverting gain circuit, such as a comparator, able to withstand radiation in an ambient space environment, and a thermistor connected to the radiation hardened inverting gain circuit so that an output frequency of the temperature sensitive oscillator varies based upon a temperature of the thermistor. Also, a frequency counter is preferably connected to the temperature sensitive oscillator for generating a digital output signal representative of a sensed temperature. The sensed temperature may be used by one or more electronic circuits connected to the frequency counter.

Abstract: A temperature stabilized CMOS oscillator circuit modifies the gain of a CMOS oscillator transistor to cancel the gain variation over temperature using a bias circuit. The bias circuit utilizes a combination of two current mirrors to establish a temperature compensating supply current to a CMOS oscillator transistor. A primary current mirror and a temperature variable resistor establish a current in the current mirror output to the CMOS oscillator transistor. A secondary current mirror and a temperature variable resistor divert current from the primary current mirror over temperature to vary the current mirror output to the CMOS oscillator transistor to compensate for its gain variation.

Abstract: An oscillator, a dielectric waveguide device and a transmitter incorporating the same, wherein a special temperature-compensating circuit provides a temperature-compensated device with reduced size and cost, and greater productivity. In the oscillator, a dielectric plate having a strip line of a specified length is arranged between conductive plates which enclose a Gunn diode. The oscillation output signal of the Gunn diode is extracted via the strip line. In addition, the sign of the dielectric-constant temperature coefficient of the dielectric plate is set such that changes in the oscillation frequency caused by changes in temperature of the Gunn diode are suppressed.

Abstract: A temperature compensated oscillator, a method of controlling a temperature compensated oscillator, and a wireless communication device are provided, where phase noise of the output signal can be reduced, frequency of the output signal stabilizes within a short time, and response of control does not become worse. Accordingly, a filter circuit is provided that removes noise contained in a temperature compensation voltage. A switching circuit is connected in parallel to this filter circuit. A power control circuit controls power supply to a voltage controlled oscillation circuit 28 and the like. The power control circuit turns on the switching circuit for a specified period when power supply to the voltage controlled oscillation circuit is started.

Abstract: An electrical device to compensate for crystal oscillator frequency shifts occurring over a temperature range includes a voltage divider for generating a temperature variable, compensation voltage at an output. The output of the voltage divider is to be electrically coupled to the oscillator so that the compensation voltage compensates for the crystal oscillator frequency shifts otherwise occurring over the temperature range. A voltage source is to be coupled to an input of the voltage divider for inputting a generally fixed voltage during normal crystal oscillator operation, and providing for multiple and repeatable adjustments to the fixed voltage before beginning the normal crystal oscillator operation.

Abstract: An improved resonant tunneling device (RTD) oscillator is provided by supplying electrical power to the RTD device 23 using a photocell 21 and a light source 25 such that essentially no spurious resonances are possible.

Abstract: Several calibration techniques for a precision relaxation oscillator with temperature compensation produces a stable clock frequency over wide variations of ambient temperature. The calibration techniques provide for different methods of determining CTAT current, PTAT current or the ratio of PTAT current to CTAT current. The calibration techniques provide different methods for determining CTAT and PTAT calibration values and for setting CTAT and PTAT calibration select switches.

Abstract: A temperature detector circuit for converting a forward drop voltage of a diode to digital data by means of an AD converter is provided. In order to restrict an occurrence of an output error caused by dispersion in diode manufacture, correction data according to digital data obtained by the AD converter is stored in advance in a storage circuit under a known arbitrary temperature condition, and subtraction is performed between digital data obtained by the AD converter under an unknown temperature condition and correction data read from a storage circuit, thereby to perform correction.

Abstract: An oscillator circuit which translates energy between electromagnetic energy and thermal energy is disclosed. The control loop of the oscillator includes a feed forward stage and a feedback stage for establishing the necessary conditions for oscillation. The signal at the output of the oscillator circuit is applied to the input of the feedback stage and the electromagnetic energy of the output signal is translated into thermal energy by a thermal element. The thermal energy is then translated back into electromagnetic energy by a thermal sensing element to generate an electronic feedback control signal. The electronic feedback control signal is then used to control the input of the feed forward stage such that the closed loop response of the system results in a periodic signal at the output of the circuit.

Abstract: An oscilator circuit for a integrated circuit memory device to optimize the refresh operating circuit and suppress wasteful power consumption in which the oscillator frequency is set high during high temperatures and the oscillator frequency is set low during low temperatures. A current I1 is generated by means of the current source 100a having characteristics in which it is increased during high temperatures and decreased during low temperatures, and is supplied to the ring oscillator 200.

Abstract: A circuit that digitizes a quantity of light received from a strobe according to the present invention, includes: a photoelectric conversion device that receives light from the strobe and generates an output corresponding to an intensity of the received light; a storage device that stores the output generated by the photoelectric conversion device; a constant quantity discharge device that holds a storage quantity at the storage device close to a specific value by discharging a constant storage quantity from the storage device over a specific period which is in synchronization with a specific sampling frequency and is shorter than the sampling cycle when the storage quantity at the storage device exceeds a predetermined threshold value and by implementing feedback control on the storage quantity at the storage device; and a received light quantity output device that outputs one or more pulse signals when the storage quantity at the storage device exceeds the predetermined threshold value.

Abstract: A phase-locking system is provided that includes a bridge, a light source and an optical pulse injector. The bridge includes a plurality of negative differential resistance devices for storing an input signal. The light source is capable of producing an optical pulse. The optical pulse injector receives the optical pulse and transmits an optical signal to trigger the bridge in response to receiving the optical pulse.

Abstract: A temperature dependent clock circuit (100) is disclosed. The clock circuit (100) includes a reference circuit (102) that provides a first group of reference signals (108) with positive temperature coefficients and a second group of reference signals (110) with negative temperature coefficients. A sample circuit (104) compares the first group of signals (108) with a second group of signals (110) and provides a group of bias signals (112) representative of the operating temperature of the clock circuit (100). A frequency controllable oscillator circuit (106) provides an output clock signal (CLK) having a frequency that is dependent upon the values of the bias signals (112).

Abstract: Several sensors are provided for determining one of a number of physical roperties including pressure, temperature, chemical species, and other physical conditions. In general, the sensors feature a resonant circuit with an inductor coil which is electromagnetically coupled to a transmitting antenna. When an excitation signal is applied to the antenna, a current is induced in the sensor circuit. This current oscillates at the resonant frequency of the sensor circuit. The resonant frequency and bandwidth of the sensor circuit is determined using an impedance analyzer, a transmitting and receiving antenna system, or a chirp interrogation system. The resonant frequency may further be determined using a simple analog circuit with a transmitter. The sensors are constructed so that either the resonant frequency or bandwidth of the sensor circuit, or both, are made to depend upon the physical properties such as pressure, temperature, presence of a chemical species, or other condition of a specific environment.

Abstract: A system that provides an accurate frequency generating source, avoids mode coupling of the quartz vibrator, and has a high production efficiency. A high frequency amplifying circuit uses a bridge circuit as part of a feed back circuit, and a quartz vibrator is inserted in a branch side connecting the CR-circuit. The oscillation frequency is less than the serial resonance frequency of the quartz vibrator. The vibration energy is enclosed between the electrodes which prevents energy scattering to a blank edge by the oscillating quartz vibrator in a shear slipping mode with a lower frequency than the serial resonating frequency. Also, occurrence of the unnecessary shear coupling mode is restricted.

Abstract: An insulating film and a conducting film are formed in that order on an N type semiconductor substrate to form a capacitor structure of “conducting film—insulating film—semiconductor”; a heavily doped P region having a high impurity concentration is provided on the N type semiconductor substrate to contact a covered region which is covered with the conducting film; and furthermore a heavily doped N region for conducting an electrode on the semiconductor side is provided and connected with the heavily doped P region, resulting in quickly variance of the capacitance values in accordance with the voltage applied between the heavily doped N region and a terminal of the conducting film.

Abstract: A crystal oscillator in which IC control terminal electrodes for writing temperature compensation data in an IC chip are formed on side surfaces of a main body while being distanced from the top and bottom surfaces of the main body. The IC control terminal electrodes will not be short-circuited with a conductive pattern for sealing the crystal oscillating element on the top surface, and the IC chip will not be destroyed by a welding current which flows when a metal cover is mounted on the top surface. The IC control terminal electrodes will not be short-circuited with other wiring conductors during the soldering to bond the crystal oscillator to a printed circuit board. The compensation data or other data written in the IC chip can be stably maintained, thereby securing a stable operation.

Abstract: Several sensors are provided for determining one of a number of physical properties including pressure, temperature, and other physical conditions. In general, the sensors feature a resonant circuit with an inductor coil which is electromagnetically coupled to a transmitting antenna. When an excitation signal is applied to the antenna, a current is induced in the sensor circuit. This current oscillates at the resonant frequency of the sensor circuit. The resonant frequency and bandwidth of the sensor circuit is determined using an impedance analyzer, a transmitting and receiving antenna system, or a chirp interrogation system. The resonant frequency may further be determined using a simple analog circuit with a transmitter. The sensors are constructed so that either the resonant frequency or bandwidth of the sensor circuit, or both, are made to depend upon the physical properties such as pressure, temperature, presence of a chemical species, or other condition of a specific environment.

Abstract: A frequency synthesizer module with temperature compensation of a crystal oscillator circuit frequency controlled by a varactor. A module memory contains information characterizing a temperature dependency of a crystal which is applied to the varactor to temperature compensate the crystal in response to a temperature sensor signal. The module includes at least one locked loop circuit including a loop filter, at least one associated frequency divider, and a switchable dual band voltage controlled oscillator. The crystal oscillator is coupled to the at least one locked loop circuit and the frequency of the crystal is controlled by the memory via the varactor such that a temperature compensated output frequency is provided by the module.

Abstract: A highly stable single chip crystal controlled oscillator with automatic gain control. An amplitude detector monitors the output of a crystal controlled oscillator amplifier and produces a feedback signal proportional to the output signal of the amplifier to ensure oscillation is induced at startup and that the amplitude of oscillation is limited to a preselected value during operation to conserve power consumption by the amplifier. The capacitor tank circuit connected to the input of the amplifier includes a voltage variable capacitor the voltage across which is initially established at manufacture to tune the oscillation frequency to a preselected value. The voltage across the voltage variable capacitor is also adjusted to compensate for temperature variations in the circuit.

Abstract: In a temperature-compensated crystal oscillator, a series connection of an AT-cut crystal resonator, a MOS capacitor, and a first fixed capacitor is coupled in parallel with an amplifier and a second fixed capacitor, making up a crystal oscillation circuit. A first control signal generating circuit for temperature compensation is connected directly or via a first input resistor to one terminal of the MOS capacitor of the crystal oscillation circuit, and a second control signal generating circuit for temperature compensation is connected dirty or via a second input resistor to the other terminal of the MOS capacitor. The first control signal generating circuit serves as a rectilinear correction signal generating circuit on the lower temperature side while the second control signal generating circuit serves as a rectilinear correction signal generating circuit on the higher temperature side.

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

Abstract: A phase locked loop ("PLL") 28 containing apparatus for automatically causing the PLL to achieve phase lock when first energized or after having lost phase lock. In addition to a phase detector 4, loop filter 13, voltage controlled oscillator ("VCO") 14 and feedback from the VCO to the phase detector 16, the PLL has a sweep circuit 30. The sweep circuit cooperates with the loop filter when the PLL is not in phase lock to automatically generate a control voltage for the VCO which control voltage increases linearly with time until the PLL achieves phase lock or until the control voltage has reached the largest voltage in the dynamic input range of the VCO. In the event that phase lock is not achieved during the period of the increasing voltage, the control voltage decreases linearly with time to drive the PLL into phase lock.

Abstract: The frequency of a quartz oscillator having a trimmer 2, a quartz oscillator 3 on which its temperature characteristic is printed in the form of a bar code 6, and a storage device 4 is adjusted to a predetermined frequency, and the temperature at that time is measured by a noncontact temperature sensor of a frequency adjusting device 10, and is written into the storage device 4. The temperature characteristic of the quartz oscillator is read by a bar code reader 21, and optimally suited temperature compensating data is selected from among a plurality of pieces of temperature compensating data stored in advance in a temperature-compensating-data writing device. Further, a frequency deviation between the temperature at the time of adjustment and a standard temperature is calculated, and the temperature compensating data including that frequency deviation is stored in the storage device 4.

Abstract: A speed measuring apparatus and a toy for measuring a speed of a moving member has a quartz oscillator for generating a clock signal which has a predetermined frequency, a CR oscillator for generating a clock signal which has a higher frequency than that of the quartz oscillator, a comparative circuit, connected with the quart oscillator and the CR oscillator, for comparing the oscillation frequency of the quartz oscillator as a reference signal with the oscillation frequency of the CR oscillator, a corrective circuit, connected with the comparative circuit, for calculating a corrective factor in accordance with a result from the comparative circuit, a measuring unit, connected with the CR oscillator and the corrective circuit, for measuring a speed of the moving member in accordance with the clock signal from the CR oscillator and the corrective factor from the corrective circuit, and a display unit, connected with the measuring unit, for displaying the speed computed by the measuring unit.

Abstract: A digital temperature compensation oscillator by which its AFC operation to a receive signal cannot be disturbed by temperature compensation operation. A digital temperature compensation oscillator comprises a temperature sensor, an address creating section, a ROM, latching means, and a voltage-controlled crystal oscillator. The temperature sensor produces an output signal varied according to ambient temperatures. The address creating section converts an output from the temperature sensor into a signal and then creating it as a ROM (read-only memory) address. The ROM stores a control voltage to compensate a frequency variation due to ambient temperatures of a voltage-controlled crystal oscillator. The latching means holds or passes data output from the ROM according to an external control signal. The D/A converter produces a control voltage for the voltage-controlled crystal oscillator according to the latching means.

Abstract: A temperature sensitive oscillator circuit and control circuit which together form a current source. The temperature sensitive oscillator circuit generates an output signal which controls a frequency of a refresh oscillator circuit. The duty cycle of the output signal of the temperature sensitive oscillator circuit is temperature dependent and increases for increases in temperature. The output signal of the temperature sensitive oscillator circuit controls the control circuit which sources current between the refresh oscillator circuit and a supply node. As the duty cycle of the output signal of the temperature sensitive oscillator circuit increases a time duration during which the control circuit sources current between the refresh oscillator circuit and the supply node increases. This increase increases the frequency of the output signal of the refresh oscillator circuit. The output signal of the refresh oscillator circuit is an internal clock signal which controls a refresh cycle of a memory circuit.

Abstract: A global positioning system (GPS) receiver and high accuracy low power time source (HAL) are disclosed. The HAL provides a time source having an accuracy which is high enough for the receiver to achieve fast direct Y-code acquisition. The HAL includes an oscillator adapted to provide an uncompensated frequency signal at a desired frequency. Frequency conversion circuitry receives the uncompensated frequency signal and a control signal as inputs, and provides as an output a compensated frequency signal having an average compensated frequency which is closer to the desired frequency than is the average uncompensated frequency. A temperature sensor provides an output indicative of a temperature of the oscillator. Frequency error determining circuitry determines an error value, as a function of the temperature sensor output, which is indicative of a quantity of frequency error over time in the uncompensated frequency signal.

Abstract: A controllable-frequency oscillator has a first portion for generating a signal having a controllable frequency. The controllable-frequency oscillator has a second portion for controlling the frequency of the signal generated by the first portion in response to a first control signal. The controllable-frequency oscillator has a third portion for controlling the frequency of the signal generated by the first portion in response to a second control signal separate from the first control signal.

Abstract: An optical PLL circuit with high precision that has its simplified configuration. An optical-intensity modulator creates difference frequency information (N.times..DELTA.f) by modulating a received optical signal formed of signal optical pulses of a repetitive frequency (N.times.f0) with a reference signal of a frequency (f0+.DELTA.f) and implementing an AND operation of them. The signal is converted into an electric signal by a photo diode. A band-pass filter extracts only the low frequency component (N.times..DELTA.f). A frequency divider produces a frequency component .DELTA.f by dividing the extracted component by N. A multiplier receives the reference signal and the output signal f of a voltage-controlled oscillator and then creates the difference frequency component ((f0+.DELTA.f)-f). A phase comparator compares the low frequency component .DELTA.f with the difference frequency component ((f0+.DELTA.f)-f) and controls the voltage-controlled oscillator to set the phase difference between them to zero.