Phase-Locked Loop Recovery from Lost Feedback Transitions
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Solution Overview
Problem
Phase-locked loops in digital systems often fail to operate due to electromagnetic and electrostatic disturbances, leading to the absence of feedback signals, which requires complete system reinitialization, an unsatisfactory solution.
Innovation Solution
A method to detect the absence of transitions in the feedback signal and lower the oscillator's control voltage until transitions reappear, without reinitializing the system, by setting a minimum operating frequency and adjusting voltage levels based on specific durations to ensure the phase-locked loop resumes operation effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the voltage-controlled oscillator operates at high frequency (e.g., 2.2 GHz), then the internal working frequency requirement is met, but the logic part cannot operate and feedback signal transitions disappear
Solution Approach 1:
The patent applies dynamics by making the oscillator frequency adjustable rather than fixed. The control voltage is dynamically modified based on the detection of feedback signal transitions. When transitions are detected, the oscillator operates at high frequency; when transitions disappear, the control voltage is lowered to bring the oscillator back within the logic part's operating range, allowing it to recover without full system reinitialization.
Solution Approach 2:
The patent changes the control voltage parameter of the voltage-controlled oscillator to resolve the contradiction. By detecting the absence of feedback signal transitions and responding by lowering the control voltage, the system adjusts the oscillator frequency from an unoperational high frequency (e.g., 2.2 GHz) back to a frequency where the logic part can function properly, thereby restoring normal operation.
2Reliability
If complete system reinitialization is performed to restore feedback signal, then the phase-locked loop can be turned back on, but system operation is interrupted and complexity increases
Solution Approach 1:
The patent implements self-service by enabling the phase-locked loop to detect and recover from its own malfunction automatically. The system monitors its own feedback signal for transitions and, upon detecting their absence, self-corrects by modifying its control voltage to restore proper operation, all without requiring external intervention or complete system reinitialization.
Solution Approach 2:
The patent uses feedback by continuously monitoring the feedback signal from the voltage-controlled oscillator for transitions. This feedback mechanism allows the system to detect when the oscillator frequency has become too high for the logic part to operate, triggering a corrective action to lower the control voltage and restore normal feedback signal generation.
3Speed
If the control signal voltage is increased to raise oscillator frequency, then the internal working frequency is improved, but the logic part fails to operate and the loop turns off
Solution Approach 1:
The patent applies dynamics by making the control signal voltage adjustable rather than fixed. The system dynamically modifies the control voltage based on real-time detection of feedback signal transitions. When transitions are present, the oscillator can operate at high frequency; when transitions disappear, the control voltage is automatically lowered to restore operability, creating a self-regulating system.
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 allows the phase-locked loop to recover from disturbances without reinitialization, ensuring stable operation by adjusting the oscillator's frequency and generating an alarm signal for malfunctions, thus preventing system crashes.
Implementation Method 1
an oscillator voltage controlled by a control signal and a phase comparator receiving a reference signal and a feedback signal which arises from the output signal of the oscillator
Data Source
AI summary
A method can be used for managing the operation of a phase-locked loop. The loop includes an oscillator voltage controlled by a control signal and a phase comparator receiving a reference signal and a feedback signal which arises from the output signal of the oscillator. The method includes a detection of a possible absence of transitions on the feedback signal for a first duration and, in response to such an absence, a forcing of the lowering of the voltage of the control signal at least until a reappearance of transitions on the feedback signal.