Programmable DFE Feedback Strength for High-Frequency Signal Recognition
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Solution Overview
Problem
Conventional decision feedback equalizers fail to effectively recognize and amplify input data with extremely high frequencies due to mismatched voltage levels between input and feedback signals, leading to inadequate feedback capability.
Innovation Solution
A decision feedback equalizer with an amplifier circuit that adjusts its driving capability based on both the decision feedback signal and a control signal, allowing for dynamic adjustment of feedback to match input signal voltages, comprising a differential amplifier circuit with a transistor pair, current source, and feedback module that increases or decreases current through feedback transistor pairs and load circuits in response to a control signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the voltage of the input signal is much higher than the voltage of the feedback signal, then the input signal can be recognized, but the feedback effect is not obvious
Solution Approach 1:
The patent applies dynamics by making the feedback path configurable through multiple switches (SW1, SW2, SW3) that can be controlled by a control signal. This allows the feedback mechanism to dynamically adjust its connection state, enabling the system to switch between different feedback modes (strong feedback, weak feedback, or no feedback) based on the input signal characteristics, thereby resolving the contradiction between input recognition and feedback effectiveness
Solution Approach 2:
The patent changes the parameter of feedback strength by introducing a control signal that adjusts the connection state of switches in the feedback path. This parameter change allows the feedback signal voltage to be dynamically adjusted relative to the input signal voltage, enabling optimal feedback capability under different voltage conditions and resolving the contradiction between maintaining input recognition and ensuring effective feedback
2Reliability
If the voltage of the input signal is much lower than the voltage of the feedback signal, then the feedback effect is strong, but the output signal becomes the feedback signal
Solution Approach 1:
The patent uses dynamic control through switches SW1, SW2, and SW3 that respond to control signals, allowing the system to adaptively adjust the feedback path configuration. When the input signal voltage is low, the control signal adjusts the switch states to reduce or disconnect the feedback path, preventing the feedback signal from overwhelming the input signal and ensuring accurate input recognition while maintaining appropriate feedback when needed
Solution Approach 2:
The patent changes the feedback path parameters (connection/disconnection) based on the relative voltage levels of input and feedback signals. The control signal modifies the electrical state of the feedback path through switch control, dynamically adjusting the feedback strength parameter to match the input signal conditions, thereby resolving the contradiction between strong feedback capability and accurate input signal recognition
3Device complexity
If a conventional decision feedback equalizer is used for high frequency input data, then the circuit structure is simple, but the amplifier cannot recognize extremely small amplitude input data
Solution Approach 1:
The patent introduces an intermediary control signal that mediates between the input signal and the feedback path. This control signal adjusts the state of switches SW1, SW2, and SW3, effectively acting as a mediator that optimizes the signal path configuration to enhance the amplifier's ability to recognize small amplitude high-frequency input data while maintaining a relatively simple circuit structure
Solution Approach 2:
The patent applies dynamics by making the feedback path configurable through multiple switches (SW1, SW2, SW3) that can be controlled by a control signal. This allows the system to dynamically adjust the feedback mechanism, enabling the amplifier to optimize its operation for recognizing small amplitude high-frequency input data without significantly increasing circuit complexity
Data Source
AI summary
A decision feedback equalizer is disclosed. The decision feedback equalizer comprises an amplifier circuit and a latch. The amplifier circuit is configured to receive an input signal, a decision feedback signal and a control signal, and is configured to adjust its driving capability according to the decision feedback signal and the control signal to provide an amplified signal of the input signal. The latch is configured to latch the amplified signal as an output signal.