Clock Generator Phase Cancellation for EMI-Induced Jitter
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Solution Overview
Problem
Integrated circuits face performance degradation due to periodic disturbances in oscillating signals caused by electromagnetic interference, leading to deterministic jitter and reduced signal quality in wireless communications systems, which existing design and packaging constraints struggle to effectively mitigate.
Innovation Solution
A clock generator system that neutralizes periodic phase perturbations by generating an auxiliary signal with opposing phase perturbations, adjusting the duty cycle, rise time, and fall time of the output clock signal to counteract induced phase disturbances, using an auxiliary path and control signals to minimize electromagnetic interference effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If shielding is used to protect the oscillator from electromagnetic interference, then the oscillator is protected from periodic disturbances, but integrated circuit design, manufacturing, and packaging constraints limit the effectiveness of shielding
Solution Approach 1:
The patent measures the harmful electromagnetic interference that couples into the oscillator and converts this harmful effect into a useful measurement signal. By measuring the interference and generating a compensating signal, the system transforms the problem of interference into a solution that actively cancels the harmful effects without requiring physical shielding.
Solution Approach 2:
The patent introduces an intermediary measurement mechanism that detects the electromagnetic interference before it fully impacts the oscillator. This measurement system acts as a mediator between the interference source and the oscillator, enabling the generation of compensating signals that neutralize the harmful effects without direct physical shielding.
2Productivity
If the output driver drives an oscillating signal off-chip, then the signal is transmitted to external systems, but this generates a time-varying magnetic field that injects energy back into the oscillator causing phase disturbances
Solution Approach 1:
The patent implements a feedback mechanism where the electromagnetic interference is measured as it couples into the oscillator, and this measurement is used to generate compensating signals. The feedback loop continuously monitors the interference and adjusts the compensation in real-time, allowing the system to maintain signal transmission while actively canceling the deterministic jitter caused by the feedback from the output driver.
Solution Approach 2:
The patent applies preliminary anti-action by measuring the interference and generating compensating signals before the harmful phase disturbances fully manifest in the oscillator output. The compensating signal is applied in advance to counteract the upcoming phase errors, preventing deterministic jitter rather than correcting it after occurrence.
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 deterministic jitter and improves signal quality by canceling out phase perturbations, enhancing the signal-to-noise ratio and reducing spurs, thereby improving the performance of wireless communications systems.
Implementation Method 1
Driving an oscillating signal off-chip generates a time-varying magnetic field that extends into the surrounding environment
Implementation Method 2
That time-varying magnetic field can inject energy into neighboring circuitry
Implementation Method 3
The auxiliary signal may be configured according to the control signal to generate a signal having a magnitude equal to a second magnitude of an induced signal in the oscillator and polarity opposite to a second polarity of the induced signal
Data Source
AI summary
A clock generator includes an oscillator configured to generate an oscillating signal and a signal path configured to provide an output clock signal based on the oscillating signal. In response to a control signal, the clock generator is configured to neutralize periodic phase perturbations in the oscillating signal using opposing periodic phase perturbations. The neutralization may occur in the signal path. The signal path may be responsive to the control signal to adjust at least one of a duty cycle, a rise time, and a fall time of the output clock signal to cause alternating phase perturbations of the periodic phase perturbations to apply as the opposing periodic phase perturbations in the output clock signal. The neutralization may occur in the oscillator. The clock generator may include an auxiliary path configured to provide an auxiliary signal to the oscillator.