Signal Modulation Circuit Phase Offset Control
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Solution Overview
Problem
High-speed signal modulation circuits face challenges in maintaining signal stability due to process variations in electronic components, leading to increased jitter in output signals, especially as transmission rates rise.
Innovation Solution
A signal modulation apparatus comprising an observation circuit, a signal modulation circuit, and a phase control circuit that generates a second signal based on a first signal and a reference clock signal, with the phase control circuit obtaining observation information on process variations and adjusting the offset between the signals to improve stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If signal transmission rate is increased by sampling at twice the frequency or above, then signal transmission rate is improved, but time margin of the signal becomes smaller making calibration more difficult
Solution Approach 1:
The patent performs phase calibration in advance before high-speed signal transmission. The calibration circuit pre-adjusts the phase relationship between clock and data signals, storing calibration results that are applied during operation. This preliminary action ensures that when high-speed transmission occurs with reduced time margins, the signals are already optimally aligned, eliminating the need for real-time calibration adjustments during fast operation.
2Reliability
If phase lock is performed via delay element or PLL circuit, then phase lock between reference clock signal and data signal is achieved, but jitter of the output signal increases due to process variation
Solution Approach 1:
The patent introduces a calibration circuit as an intermediary between the reference clock signal and the data signal. This calibration circuit measures the actual phase relationship and generates correction signals that compensate for process variations. By using this intermediate calibration stage, the system achieves accurate phase locking without the jitter amplification problems that occur when relying solely on delay elements or PLL circuits that are sensitive to process variations.
Solution Approach 2:
The calibration circuit implements a feedback mechanism where the actual phase relationship between clock and data signals is continuously monitored and measured. Based on this feedback information, the system adjusts the phase alignment to optimize the signal relationship. This feedback loop compensates for process variations in real-time, preventing the jitter accumulation that would otherwise occur in open-loop delay element or PLL-based systems.
3Speed
If sampling frequency is increased to meet high-speed transmission requirements, then transmission rate is improved, but calibration between reference clock signal and data signal becomes more difficult
Solution Approach 1:
The calibration circuit is designed to automatically perform phase calibration without requiring external intervention or complex manual adjustment procedures. The circuit self-measures the phase relationship between clock and data signals and automatically generates the necessary correction signals. This self-service capability simplifies the overall system complexity despite operating at high speeds, as the calibration function is autonomously handled by dedicated circuitry rather than requiring complex external calibration equipment or procedures.
Data Source
AI summary
A signal modulation apparatus, a memory storage apparatus, and a signal modulation method are disclosed. The signal modulation apparatus includes an observation circuit, a signal modulation circuit, and a phase control circuit. The signal modulation circuit is configured to generate a second signal according to a first signal and a reference clock signal. A frequency of the first signal is different from a frequency of the second signal. The phase control circuit is configured to obtain an observation information via the observation circuit. The observation information reflects a process variation of at least one electronic component in the signal modulation apparatus. The phase control circuit is further configured to control an offset between the first signal and the reference clock signal according to the observation information.