Abstract: Systems and processes disclosed herein determine the temperature of a crystal, such as a crystal that may be used in a crystal oscillator, using the reference crystal itself. The system can measure the temperature of the crystal without a temperature sensor. Further, a single oven technique may be used to maintain the temperature of the reference crystal. Thus, in certain embodiments, a more compact crystal oscillator can be generated compared to conventional techniques. Further, by measuring the reference crystal based on signals generated by the reference crystal itself, the system disclosed herein is more accurate than many previous crystal oscillator systems.

Abstract: Systems and processes disclosed herein determine the temperature of a crystal, such as a crystal that may be used in a crystal oscillator, using the reference crystal itself. The system can measure the temperature of the crystal without a temperature sensor. Further, a single oven technique may be used to maintain the temperature of the reference crystal. Thus, in certain embodiments, a more compact crystal oscillator can be generated compared to conventional techniques. Further, by measuring the reference crystal based on signals generated by the reference crystal itself, the system disclosed herein is more accurate than many previous crystal oscillator systems.

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 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: An ovenized oscillator has two ovens. One of the ovens is heated by a heater and the other is cooled by a thermoelectric module. The ovenized oscillator has an inner oven with an oscillator located inside. A thermoelectric heat pump cools the inner oven. An outer oven contains the inner oven and the thermoelectric heat pump. A heater heats the outer oven. The ovenized oscillator is operated with the inner oven temperature being lower than the outer oven temperature to improve component life and reduce crystal aging.

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: 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: A miniature ovenized crystal oscillator has a ceramic case that has a cavity, a bottom and a ledge that extends into the cavity. The case has several circuit lines. A substrate is located in the cavity and is supported by the ledge. The substrate has a top and bottom surface and several circuit lines. A crystal is mounted to the bottom surface of the substrate and is connected to the substrate circuit lines. A signal conditioning circuit is mounted to the top surface of the substrate and is connected to the substrate circuit lines. The case circuit lines are connected to the substrate circuit lines by a conductive epoxy. A heater is mounted to the bottom of the ceramic case. A thermal adhesive is located between the heater and the crystal. The thermal adhesive thermally links the crystal and the heater.

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: A temperature compensated crystal oscillator using an AT cut crystal produces a reference frequency. The temperature compensated crystal oscillator is located inside a temperature controlled oven. The temperature controlled oven provides a stable temperature to the temperature compensated crystal oscillator such that deviations from the reference frequency are reduced.

Abstract: A low profile integrated oscillator operable to provide an oscillator signal includes a thermally conductive substrate having a cavity and a ledge. A crystal or other resonator is located in the cavity and mounted to the ledge. The resonator stabilizes the oscillator signal. An electrical circuit is mounted to the substrate and electrically connects to the resonator to condition the oscillator signal. A cover seals the resonator in the cavity. A via electrically connects the resonator to the electrical circuit. A heater is mounted to the substrate, outside the cavity, for elevating the temperature inside the cavity and a temperature sensor is mounted to the substrate to monitor the oscillator temperature. The substrate is surrounded by an insulation and mounted within a housing. The housing has a connector for connecting to an external electrical circuit.

Abstract: A heater control system for ovenized oscillators that is capable of changing the relative influence of multiple temperature sensors in order to keep a uniform temperature profile across the oscillator enclosure. A resonator is located near a heater in an enclosure. Several temperature sensors are located in proximity to the resonator for sensing temperature. One of the sensors is closer to the heater and another sensor is closer to an outer wall of the enclosure. A control circuit is connected between the sensors and the heater to provide a control signal to the heater, in response to the sensors. An adjustment circuit is connected to each of the sensors, for adjusting the relative influence that each sensor has on the control circuit.

Abstract: A low profile integrated oscillator operable to provide an oscillator signal includes a substrate having a cavity and a via passing through the substrate. A crystal or other resonator is disposed in the cavity and stabilizes the oscillator signal. An electrical circuit means is mounted to the substrate and electrically connects to the via to condition the oscillator signal. A cover seals the resonator in the cavity. A connector electrically connects the resonator to the via. A heater is mounted to the substrate to elevate the oscillator temperature and a temperature sensor is mounted to the substrate to monitor and control the oscillator temperature. The substrate is surrounded by an insulation and mounted within a housing. The housing has a connection means for connecting to an external electrical circuit.