Echo Cancellation Circuit Using Pulse-Shaped Analog Subtraction
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Solution Overview
Problem
Communication devices face challenges in eliminating echo and crosstalk, which interfere with signal reception and require complex analog to digital converter designs with large dynamic ranges, increasing production costs.
Innovation Solution
A communication device incorporating a level determining module, digital to analog converter, and analog to digital converter that generates a pulse-shaped analog signal to eliminate interference responses, allowing the back end circuit to acquire complete channel information and reduce the dynamic range of the analog to digital converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dynamic range of the analog to digital converter is increased to completely receive and process both the weak signal and strong echo signal, then the signal reception capability is improved, but the design complexity and production cost increase
Solution Approach 1:
The patent segments the signal processing into two distinct paths: an analog processing path for the weak received signal and a digital processing path for the strong echo signal. The analog to digital converter only needs to handle the weak signal with limited dynamic range, while echo cancellation is performed digitally after conversion. This segmentation allows each component to be optimized independently, reducing the overall system complexity.
Solution Approach 2:
The patent introduces an intermediary analog to digital converter that acts as a bridge between the analog domain (weak signal) and digital domain (echo processing). By converting the weak signal to digital form first, the system can then apply digital signal processing techniques for echo cancellation without requiring the analog to digital converter to handle the full dynamic range of both signals simultaneously.
2Object-affected harmful factors
If the dynamic range of the analog to digital converter is increased to handle both signals, then the echo and crosstalk elimination capability is improved, but the production cost increases
Solution Approach 1:
The patent replaces the requirement for a high dynamic range analog to digital converter with a combination of analog subtraction circuitry and digital processing. Instead of relying on the analog to digital converter to handle the full dynamic range, the system uses analog subtraction to remove the echo signal before conversion, thereby reducing the dynamic range requirement and production cost of the analog to digital converter while maintaining echo elimination capability.
3Reliability
If the analog to digital converter is designed with large dynamic range to process both signals, then the communication quality is improved, but the device complexity increases
Solution Approach 1:
The patent performs preliminary echo subtraction in the analog domain before the signal enters the analog to digital converter. By removing the echo component beforehand, the converter only needs to process the weak received signal with limited dynamic range, simplifying the overall device architecture while maintaining communication quality. The digital processing stage then completes the echo cancellation without requiring complex analog-to-digital conversion.
Data Source
AI summary
A communication device and the method thereof are disclosed in embodiments of the present invention. The communication device includes a level determining module, an digital to analog converter and an analog to digital converter. The level determining module determines a plurality of voltage levels and voltage intensity thereof according to an estimating signal to generate a first digital signal. The digital to analog converter converts the first digital signal into a pulse shaped analog signal according to the plurality of voltage levels and voltage intensity thereof. The analog to digital converter converts a first difference signal into a second digital signal wherein the first difference signal equals the result of subtracting the pulse shaped analog signal from a receiving signal.