Hysteresis Comparator Circuit for Fast Burst Optical Signal Response
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing signal response circuits in high-speed burst receive mode optical line terminal apparatus face challenges in achieving fast and accurate responses without clock data recovery (CDR), particularly in passive optical networks (PON) where increasing internet speed demands faster data transmission.
Innovation Solution
A fast signal response circuit with hysteresis control is introduced, comprising a switch element and a comparator that automatically switches between two reference signals based on a control signal, allowing for rapid and accurate response to light input sensing signals, independent of internet speed and CDR, and equipped with hysteresis control functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a microcontroller is used to determine light input signal intensity, then the circuit can be simplified, but the response speed becomes too slow for high-speed burst receive mode
Solution Approach 1:
The patent replaces the microcontroller-based digital control system with an analog circuit system comprising a comparator, switch element, and reference signal generation circuit. This substitution eliminates the need for software processing and microcontroller intervention, achieving nanosecond-level response speeds suitable for high-speed burst receive mode while maintaining circuit functionality for light input signal detection and hysteresis control.
Solution Approach 2:
The patent pre-generates multiple reference signals with different intensity levels and stores them in a reference signal generation circuit before they are needed. When a light input signal is detected, the comparator immediately compares the signal against these pre-prepared reference signals and switches between them based on the comparison result, eliminating any delay associated with generating or processing reference signals in real-time.
2Speed
If high-speed response is achieved without CDR, then data transmission speed can increase, but signal response accuracy deteriorates
Solution Approach 1:
The patent implements a hysteresis control mechanism where the comparator output feeds back to control the switch element, which in turn selects reference signals for subsequent comparisons. This feedback loop creates stable switching thresholds that prevent oscillation around decision boundaries, ensuring accurate signal intensity determination even at high data transmission speeds without requiring clock data recovery (CDR).
Solution Approach 2:
The patent dynamically changes the reference signal parameter (intensity level) based on the control signal from the comparator. By switching between multiple reference signals with different intensity levels, the system adapts its comparison threshold to match the incoming light input signal characteristics, maintaining measurement precision across varying signal conditions while operating at high speeds.
Data Source
AI summary
A fast signal response circuit with hysteresis control includes a switch element and a comparator. The switch element includes a first and a second input terminals and a control terminal, the first terminal is configured to receive a first reference signal, the second terminal is configured to receive a second reference signal, the control terminal is configured to receive a control signal, and the switch element is configured to output the first or the second reference signal through a first output terminal according to the control signal. The comparator includes a third input terminal, a fourth input terminal and a second output terminal, the third input terminal is connected to the first output terminal, the fourth input terminal is configured to receive a sensing signal corresponding to a light input, and the second output terminal is connected to the controller and is configured to output the comparison result.