Signal transmission circuit
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Solution Overview
Problem
In signal transmission, the quality of digital signals is compromised when transmitted through a common interface with analog signals due to interference from analog switches, leading to potential communication failures, especially in applications like USB type-C connectors where both digital and analog signals are multiplexed.
Innovation Solution
A signal transmission circuit is designed with a common interface, a first switch for digital signals, a second switch for analog signals, and an interference-resistant branch that eliminates interference from the analog switch, using impedance matching circuits to offset capacitive or inductive interference, ensuring high-quality digital signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If digital signal and analog signal are transmitted through the same common interface, then the number of output interfaces is reduced, but the quality of digital signal is degraded due to interference from analog switch
Solution Approach 1:
An interference-resistant branch is introduced as an intermediary element between the analog switch and the common interface. This branch includes impedance matching circuits that act as mediators to cancel out the capacitive interference generated by the analog switch, thereby protecting the digital signal quality while maintaining interface multiplexing functionality
Solution Approach 2:
The interference-resistant branch is configured to preemptively counteract the interference from the analog switch before it affects the digital signal. By using impedance matching circuits that generate opposite-phase interference signals, the system preliminarily neutralizes the harmful capacitive coupling effects, preventing signal degradation before it occurs
2Adaptability or versatility
If analog switch is used for analog signal transmission through common interface, then interface multiplexing is achieved, but interference is introduced to digital signal
Solution Approach 1:
The interference-resistant branch converts the harmful capacitive interference from the analog switch into a beneficial effect. By using impedance matching circuits that generate counter-phase signals, the previously harmful interference is transformed into a canceling force that actively neutralizes the analog switch's capacitive coupling effects, thereby protecting digital signal integrity
Solution Approach 2:
The impedance matching circuits in the interference-resistant branch dynamically adjust impedance parameters to match and counteract the capacitive characteristics of the analog switch. By changing the electrical parameters (impedance, phase) of the interference-resistant branch, the system optimally cancels out the harmful interference across different operating conditions
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 interference from analog switches, ensuring reliable digital signal transmission and maintaining communication quality, even when both digital and analog signals share the same interface, such as in USB type-C connectors.
Implementation Method 1
using impedance matching circuits to offset capacitive or inductive interference
Data Source
AI summary
Disclosed is a signal transmission circuit, comprising: a common interface, a first switch, a second switch, and an interference-resistant branch; the common interface is configured to, receive a digital signal through the first switch when the first switch is closed, or to receive an analog signal through the second switch when the second switch is closed; the interference-resistant branch is configured to eliminate an interference of the second switch on the digital signal; a signal input of the interference-resistant branch is configured to receive the digital signal, and a signal output of the interference-resistant branch is connected to a signal input of the first switch; and/or, the signal input of the interference-resistant branch is connected to a signal output of the second switch, and the signal output of the interference-resistant branch is connected to a signal input of the common interface.