Reference Clock Switching to Mitigate Spurious Frequency Components
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Solution Overview
Problem
Existing methods for eliminating spurious signals in electronic devices fail to address the challenge of spurious signals, which are not effectively addressed, leading to inefficiencies and costs.
Innovation Solution
A method and apparatus for generating and selecting a reference clock signal using a multiplexer to switch between two clock signals, one generated by an oscillator and another by a frequency synthesizer, based on the presence of spurious frequency components detected by a processor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a single clock signal source is used, then device complexity is reduced, but spurious signals cannot be effectively eliminated
Solution Approach 1:
The clock signal generation system is segmented into multiple independent sources: an oscillator generating a first clock signal and a frequency synthesizer generating a second clock signal. This segmentation allows each source to be independently evaluated and selected based on spurious signal characteristics, effectively eliminating harmful frequencies while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
The system changes the frequency parameter by generating two clock signals at different frequencies from the same reference oscillator. The frequency synthesizer derives a second clock signal with a different frequency from the first clock signal, allowing the system to switch between frequency parameters to avoid spurious signals at specific frequencies.
2Reliability
If clock signal sources are monitored and switched dynamically, then spurious signals are eliminated, but device complexity increases
Solution Approach 1:
The system implements feedback by continuously monitoring the output clock signal for spurious frequency components using a spectrum analyzer or frequency detector. When spurious signals are detected, the control logic receives feedback and automatically switches from the currently active clock source to the alternative source, ensuring high reliability through closed-loop control while managing complexity through automated decision-making.
Solution Approach 2:
A multiplexer serves as an intermediary component that receives both the first clock signal from the oscillator and the second clock signal from the frequency synthesizer. The multiplexer is controlled by control logic that determines which signal source to pass through based on spurious signal detection, thereby isolating the complexity of source selection from the rest of the system and simplifying the overall architecture.
3Object-affected harmful factors
If multiple clock signal sources are used, then spurious signals can be eliminated, but manufacturing cost increases
Solution Approach 1:
A single reference oscillator serves multiple functions by generating both the first clock signal directly and providing the reference for the frequency synthesizer to generate the second clock signal. This multi-functionality reduces manufacturing cost by eliminating the need for two completely independent oscillator circuits, while still achieving spurious signal elimination through the dual-source architecture.
Solution Approach 2:
The system performs preliminary action by pre-generating both the first clock signal from the oscillator and the second clock signal from the frequency synthesizer before operation begins. The control logic pre-evaluates which source is more suitable based on expected operating conditions and spurious signal characteristics, allowing the system to start with the optimal clock source already identified, thereby reducing the need for expensive real-time analysis and switching components.
Data Source
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AI summary
A method for providing a reference clock signal, comprising: generating, by an oscillator, a first clock signal having a first frequency, the first clock signal being coupled to a frequency synthesizer; generating, by the frequency synthesizer, a second clock signal based on the first clock signal, the second clock signal having a second frequency different from the first frequency; outputting a reference clock signal to one or more components of an electronic device, the reference clock signal being one of the first clock signal or the second clock signal; identifying one or more spurious frequency components; and monitoring the reference clock signal for a presence of the one or more spurious frequency components, the monitoring comprising: in response to determining the presence of at least one of the one or more spurious frequency components, selecting a different one of the first clock signal or the second clock signal to be the reference clock signal.