Multi-Mode Oscillator Circuit for Sensorless Temperature Compensation
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Solution Overview
Problem
Electronic oscillator circuits, particularly those using quartz crystals and MEMS resonators, face significant temperature sensitivity issues, leading to accuracy limitations of tens of parts per million over a relevant temperature range, which is inferior to Caesium and Rubidium oscillators, and existing compensation methods often introduce new temperature effects or require bulky components.
Innovation Solution
A multi-mode oscillator circuit with temperature stabilization, utilizing a processor to determine temperature by measuring the mutual proportion of simultaneous resonance modes and applying a prestored compensation factor, and employing a down conversion oscillator with a low pass filter to separate and stabilize oscillation frequencies, eliminating the need for a separate temperature sensor and reducing noise and aging effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate temperature sensor is used to compensate crystal frequency deviation, then temperature compensation can be achieved, but the measurement device introduces new temperature effects in the crystal and limits dynamic response
Solution Approach 1:
The resonator itself serves as the temperature sensor by utilizing its own temperature-dependent resonance frequency characteristics. The system measures the resonance frequency of the resonator to determine temperature, eliminating the need for separate temperature sensors that would introduce additional thermal effects or response delays.
Solution Approach 2:
The resonator performs dual functions: generating the oscillation signal and serving as the temperature sensing element. By exploiting the temperature dependence of the resonator's own resonance frequency, the system combines frequency generation and temperature measurement in a single component.
2Ease of manufacture
If quartz crystals or MEMS resonators are used for lower accuracy applications, then cost is reduced and integration is simplified, but temperature stability deteriorates to tens of parts per million
Solution Approach 1:
The system continuously measures the resonance frequency of the resonator, determines the corresponding temperature, and applies real-time compensation to the oscillation frequency. This feedback loop enables standard quartz crystals and MEMS resonators to achieve frequency accuracy in the parts per billion range, comparable to expensive atomic oscillators.
Solution Approach 2:
The system changes the operating parameters by utilizing the temperature-dependent resonance frequency of the resonator as a sensing parameter. By measuring how the resonance frequency shifts with temperature and applying compensation based on these measurements, the system transforms a source of error into a useful measurement parameter.
3Measurement precision
If Caesium or Rubidium oscillators are used to achieve high accuracy, then frequency precision improves to parts per trillion, but manufacturing cost increases significantly
Solution Approach 1:
The system replicates the high accuracy performance of atomic oscillators using much cheaper quartz crystals or MEMS resonators. By copying the frequency stabilization approach through electronic compensation based on resonator temperature measurements, the system achieves parts per billion accuracy without requiring expensive atomic materials.
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 enhances the accuracy of oscillator circuits to the range of a few parts per billion, improves integration by eliminating the need for separate temperature sensors, and reduces noise and aging-related errors, achieving robust and precise frequency stabilization.
Implementation Method 1
Driving a quartz crystal is simple as quartz shows piezoelectric behaviour, meaning that the accurate mechanical vibration properties of a crystal are easily driven and read by electronics.
Implementation Method 2
Electronic oscillator circuits generally comprise an element that causes an oscillation, or that can be brought in resonance, and then causes an oscillation.
Data Source
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AI summary
Electronic oscillator circuit, comprising a first oscillator, for supplying a first oscillation signal, a second oscillator, for supplying a second oscillation signal, a first controller for delivering the first control signal as a function of a phase difference between a first controller input and a second controller input of the first controller; a second controller for delivering the second control signal as a function of a phase difference between a first controller input of the second controller and a second controller input of the second controller; a resonator; at least a second resonance frequency, with a first phase shift dependent on the difference between the frequency of a second exciting signal and the second resonance frequency and processing means, for receiving the first oscillator signal and the second oscillator signal, determining their mutual proportion, looking up a frequency compensation factor in a prestored table and outputting a compensated oscillation signal.