Optical Line Terminal DC Offset Calibration for Burst Settling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high-speed uplink communication networks, the long burst settling time of the limiting amplifier in optical line terminals leads to increased overheads and reduced bandwidth utilization, making it difficult to meet the growing demand for symmetric transmission rates.
Innovation Solution
A signal processing apparatus with a reset signal generation unit, signal amplification and equalization unit, and direct-current offset calibration loop units that adjusts and calibrates the direct-current offset during data burst block intervals, rather than only when data is being transmitted, to reduce the burst settling time and improve bandwidth utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct-current offset calibration is performed only during data transmission, then signal accuracy is maintained, but burst settling time increases and bandwidth utilization decreases
Solution Approach 1:
The patent performs direct-current offset calibration during idle intervals before data transmission begins. The calibration circuit activates during these idle periods to adjust and equalize the direct-current offset of the limiting amplifier, ensuring that when data transmission starts, the offset is already optimized. This preliminary calibration action reduces burst settling time while maintaining signal accuracy during actual data transmission.
2Measurement precision
If direct-current offset calibration is performed continuously, then signal accuracy is improved, but overhead increases and bandwidth utilization decreases
Solution Approach 1:
The patent implements periodic calibration during idle intervals rather than continuous calibration. The calibration circuit is activated periodically during idle periods between data bursts, allowing the system to maintain signal accuracy while minimizing interference with data transmission. This periodic approach ensures the limiting amplifier is recalibrated when needed without continuously occupying the transmission channel, thus preserving bandwidth utilization.
3Productivity
If burst settling time is reduced, then bandwidth utilization improves, but signal calibration accuracy may deteriorate
Solution Approach 1:
The patent performs complete and thorough direct-current offset calibration during idle intervals before data transmission begins. By utilizing the idle period for comprehensive calibration adjustments, the system ensures that the limiting amplifier is fully optimized before data bursts start. This preliminary action allows sufficient time for accurate calibration without encroaching on data transmission time, thus maintaining calibration accuracy while improving bandwidth utilization during actual data transmission.
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention provides a signal processing apparatus, an optical line terminal, and a communications system. The signal processing apparatus includes a signal input interface, a signal output interface, a reset signal generation unit, a signal amplification and equalization unit, an enable signal generation unit, and N direct-current offset calibration loop units. The signal input interface is connected to the signal amplification and equalization unit, the signal amplification and equalization unit is connected to the signal output interface and the enable signal generation unit, the enable signal generation unit is connected to the N direct-current offset calibration loop units, the N direct-current offset calibration loop units are connected to the signal amplification and equalization unit, and the reset signal generation unit is connected to the N direct-current offset calibration loop units. The signal processing apparatus, the optical line terminal, and the communications system provided in the present invention can reduce an LA burst settling time, thereby reducing physical overheads of a link.