Mobile Terminal Clock Architecture for Harmonic EMI Control
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Solution Overview
Problem
In mobile terminals, adjacent modules experience electromagnetic interference due to similar clock frequencies, leading to malfunctions such as slow fingerprint unlock speeds, stalling during shooting, key linkage issues, and broken lines on touch panels, despite the use of frequency-domain management methods and different crystal oscillators, as ambient temperature affects clock frequencies, causing harmonic interference.
Innovation Solution
A mobile terminal design that uses a single crystal oscillator to generate clocks for multiple modules through frequency conversion circuits, ensuring that clock frequencies have the same temperature drift amplitude, thereby minimizing electromagnetic interference by maintaining a consistent frequency spacing between harmonic frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If different crystal oscillators are configured for modules to generate clocks with different frequencies, then electromagnetic interference between modules is reduced, but clock frequencies deviate at different amplitudes under ambient temperature impact, causing harmonic interference
Solution Approach 1:
The patent merges the clock generation function into a single crystal oscillator that serves multiple modules, rather than using separate oscillators for each module. This unified approach ensures that all modules share the same temperature characteristics and frequency drift behavior, eliminating the harmonic interference problem caused by differential drift while maintaining frequency separation through division relationships
Solution Approach 2:
The patent changes the frequency parameter relationship between modules by using a division relationship (where one clock frequency is N times another) instead of using completely different oscillators. This parameter change ensures that frequency spacing remains consistent even under temperature variations, as all frequencies derive from the same source and scale uniformly with temperature
2Stability of the object's composition
If a single crystal oscillator is used to generate clocks for multiple modules, then temperature drift amplitude is consistent across modules, but frequency-domain management becomes more complex
Solution Approach 1:
The patent segments the frequency output from a single crystal oscillator by using frequency division circuits that divide the base clock frequency by different integers (N, M, etc.) to generate different clock frequencies for different modules. This segmentation approach simplifies the overall system by using one stable oscillator while creating multiple frequency channels through mathematical division, reducing the complexity compared to managing multiple independent oscillators
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 effectively reduces harmonic interference caused by temperature drift, ensuring low electromagnetic interference and maintaining module functionality even under temperature variations, as shown by the consistent spectral deviations and anti-interference capabilities.
Implementation Method 1
a frequency conversion circuit connected to both the clock generator and the first module, and configured to: perform frequency conversion on a clock signal generated by the clock generator, to obtain a first clock signal, and output the first clock signal to the first module
Implementation Method 2
a clock generator, and a first frequency conversion circuit connected to both the clock generator and the first module
Data Source
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AI summary
This application discloses a mobile terminal, including a clock generator, a first frequency conversion circuit, a first module, a second frequency conversion circuit, and a second module. The first frequency conversion circuit performs frequency conversion on a clock signal generated by the clock generator, to obtain a first clock signal, and outputs the first clock signal to the first module. The second frequency conversion circuit performs frequency conversion on the clock signal generated by the clock generator, to obtain a second clock signal, and outputs the second clock signal to the second module. The mobile terminal in this application has a better anti-electromagnetic interference capability.