Injection-Locked Phase Interpolation for Skew and Jitter Reduction
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Solution Overview
Problem
Data communication systems, such as PONs, face challenges in skew and jitter reduction due to static and dynamic skew in clock signal paths, affecting the sampling margins of receivers.
Innovation Solution
A system comprising a first and second phase interpolator, and a circuit configured as an injection locked oscillator, with amplifiers and switches to generate multiple phase signals, and buffers to correct skew using skew control signals, providing improved phase interpolation and clock signal generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If phase interpolators are used to offset transmit phase over time and frequency, then the SERDES can transmit data at the same frequency as far-end peer device, but static and dynamic skew of interleaved clock paths affects sampling margins
Solution Approach 1:
The system divides the clock signal generation into multiple independent phase interpolators (first and second phase interpolators), each handling specific phase signals. This segmentation allows independent optimization and control of each interpolator's output, reducing the impact of skew on overall system reliability.
Solution Approach 2:
The injection locked oscillator provides a feedback mechanism where the phase relationships between multiple clock signals are continuously monitored and adjusted. The oscillator locks to the combined input signals, automatically compensating for skew and maintaining stable phase relationships, thereby improving sampling margins.
2Measurement precision
If multiple phase signals are generated to improve phase interpolation resolution, then linearity and resolution are enhanced, but device complexity increases
Solution Approach 1:
The injection locked oscillator serves multiple functions simultaneously: it generates multiple phase signals, provides frequency synthesis, and performs phase locking. This multi-functionality allows the system to achieve high phase interpolation resolution without proportionally increasing device complexity, as a single circuit block accomplishes what would otherwise require multiple separate components.
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
The solution effectively reduces skew and jitter, enhancing the linearity and resolution of phase interpolation, and improving the robustness of clock signals across variations in processing, voltage, and temperature.
Implementation Method 1
the first circuit is configured as an injection locked oscillator
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A system (200) includes a first phase interpolator (204), a second phase interpolator (206), and a circuit (208). The circuit is configured to receive a first signal and a second signal provided by the first phase interpolator and a third signal and a fourth signal provided by the second phase interpolator. The first circuit is configured to provide at least eight phase signals, each of the eight phase signals being at a respective phase angle in response to the first signal, the second signal, the third signal and the fourth signal.