Dual Quartz Oscillator Temperature Compensation by Frequency Difference
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Solution Overview
Problem
Existing temperature-compensated quartz-crystal oscillators (TCXOs) face challenges in achieving high frequency accuracy due to limitations in temperature detection accuracy and the complexity of manufacturing processes, which result in frequency stability issues and prolonged manufacturing times.
Innovation Solution
The oscillation device employs two quartz-crystal resonators with different electrode configurations to detect frequency differences, using these differences to calculate a frequency correction value that accurately compensates for environmental temperature changes, thereby stabilizing the output frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a thermistor is used as the temperature detector, then the device structure is simple, but the temperature detection accuracy is limited
Solution Approach 1:
The patent creates a virtual temperature sensor by copying the frequency-temperature characteristic of the quartz-crystal resonator through software modeling. Instead of using a physical thermistor, the system measures the actual frequency-temperature relationship of the resonator and generates a virtual sensor that replicates this characteristic, thereby achieving high temperature detection accuracy without adding complex hardware.
Solution Approach 2:
The patent replaces the mechanical/physical temperature sensing system (thermistor) with an electronic/software-based system. By measuring the frequency output of the quartz-crystal resonator and using pre-stored frequency-temperature characteristic data, the system calculates temperature without physical contact or additional temperature-sensitive components, thus improving accuracy while maintaining structural simplicity.
2Device complexity
If the temperature detector and quartz-crystal resonator are disposed at different positions, then the device structure is simplified, but the actual temperature information of the resonator cannot be accurately obtained
Solution Approach 1:
The patent implements a feedback mechanism where the frequency output of the quartz-crystal resonator is continuously measured and fed back to the control unit. By comparing the measured frequency with the pre-stored frequency-temperature characteristic data, the system derives the actual temperature of the resonator, ensuring accurate temperature information is obtained regardless of the physical position of the temperature detector.
3Manufacturing precision
If frequency measurement is performed in a thermostatic oven with temperature variation, then the temperature compensation amounts can be individually set, but the manufacturing time is prolonged due to waiting for temperature stabilization
Solution Approach 1:
The patent performs preliminary action by pre-measuring and storing the frequency-temperature characteristic data of the quartz-crystal resonator during the manufacturing process. This data is saved in the control unit's memory, eliminating the need for repeated temperature stabilization and measurement cycles during production. The resonator's frequency-temperature characteristics are captured once and reused for temperature compensation, significantly reducing manufacturing time while maintaining measurement accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables highly accurate temperature compensation of the output frequency, simplifies the manufacturing process, and reduces production time by eliminating the need for precise temperature control and complex frequency adjustments.
Implementation Method 1
a first quartz-crystal resonator (10) including a first electrode (11, 12) provided on a quartz-crystal piece (Xb); a second quartz-crystal resonator (20) including a second electrode (21, 22) provided on a quartz-crystal piece (Xb)
Data Source
AI summary
An oscillation device capable of highly accurate temperature compensation of an output frequency is provided. The oscillation device includes: first and second oscillator circuits oscillating first and second quartz-crystal resonators with overtones respectively; a frequency difference detecting part finding a value corresponding to a difference value between values corresponding to differences between f1 and f1r and between f2 and f2r, where f1 and f2 are oscillation frequencies of the first and second oscillator circuits, and f1r and f2r are oscillation frequencies of the first and second oscillator circuits at a reference temperature; and a correction value obtaining part which, based on the value corresponding to the difference value and a relation between the value corresponding to the difference value and a frequency correction value of the oscillation frequency f1, obtains the frequency correction value of f1, wherein the output frequency is corrected based on the found frequency correction value.