Heated Crystal Oscillator Package for Stable Filter Attenuation
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Solution Overview
Problem
Oven-controlled crystal oscillators improve frequency stability by maintaining a constant temperature for the crystal unit but neglect the temperature-dependent attenuation characteristics of the crystal filter, leading to inadequate noise removal at varying ambient temperatures.
Innovation Solution
Incorporating a heating portion with resistors between the wiring board and package to control the ambient temperature of both the crystal unit and crystal filter, ensuring accurate temperature management and improved noise characteristics by maintaining a constant frequency response across temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heater circuit is disposed to control the temperature of the crystal unit in the oscillator circuit, then the frequency stability of the oscillation signal is improved, but the temperature characteristic of the crystal filter is not considered, leading to shifted attenuation characteristics and inadequate noise removal
Solution Approach 1:
The heater circuit is designed to serve dual purposes: it heats both the crystal unit in the oscillator circuit and the crystal filter simultaneously. This multi-functional approach ensures that both components operate at their optimal temperatures, maintaining frequency stability while preserving the attenuation characteristics of the crystal filter for effective noise removal.
Solution Approach 2:
The patent combines the temperature control function for both the crystal unit and crystal filter into a single heater circuit system. By merging these two temperature control functions, the system achieves coordinated thermal management, ensuring that both components maintain their respective frequency and attenuation characteristics without requiring separate heating mechanisms.
2Object-generated harmful factors
If the crystal filter is used to remove noise components, then the noise characteristic of the oscillation signal is improved, but the attenuation characteristic shifts with temperature changes, reducing effectiveness at varying temperatures
Solution Approach 1:
The patent applies parameter changes by actively controlling the temperature of the crystal filter through the heater circuit. By adjusting the temperature parameter of the crystal filter to remain constant despite ambient temperature variations, the attenuation characteristic is stabilized, ensuring consistent noise removal performance across different operating conditions.
Solution Approach 2:
The system implements feedback control where the heater circuit continuously monitors and adjusts the temperature of the crystal filter to maintain optimal attenuation characteristics. This feedback mechanism ensures that the crystal filter operates at the temperature required for effective noise removal, compensating for any ambient temperature changes that would otherwise shift the attenuation characteristic.
3Reliability
If separate temperature control for crystal unit and crystal filter is implemented, then both frequency stability and noise removal are optimized, but the device complexity increases
Solution Approach 1:
The heater circuit is designed as a universal temperature control system that simultaneously serves both the crystal unit and the crystal filter. This multi-functional design eliminates the need for separate heater circuits for each component, reducing device complexity while maintaining optimized frequency stability and noise removal performance.
Solution Approach 2:
The patent merges the temperature control functions for the crystal unit and crystal filter into a single integrated heater circuit system. By combining these functions, the system achieves the reliability benefits of separate temperature optimization without the complexity overhead of completely independent control systems, as both components share the same thermal management infrastructure.
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 solution enhances the noise characteristics of the oscillation signal by ensuring the crystal filter's attenuation characteristic aligns with the oscillation frequency, effectively removing unnecessary noise components regardless of temperature fluctuations.
Implementation Method 1
The heating portion is configured to heat the crystal blank of the oscillator circuit and the crystal blank of the crystal filter by using a resistor disposed between a wiring board to which the package portion is secured, and the package portion
Data Source
AI summary
An oscillator includes an oscillator circuit, a crystal filter, a package portion, and a heating portion. The oscillator circuit is configured to output an oscillation signal. The crystal filter has a frequency characteristic where an attenuation at a detuned frequency is larger than an attenuation at an oscillation frequency of the oscillation signal. The detuned frequency is a frequency different from the oscillation frequency. The package portion covers a crystal blank of the oscillator circuit and a crystal blank of the crystal filter. The heating portion is configured to heat the crystal blank of the oscillator circuit and the crystal blank of the crystal filter using a resistor disposed between: a wiring board to which the package portion is secured, and the package portion.