Echo Cancellation Transceiver Using Segmented Analog-Digital Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high-speed in-vehicle Ethernet systems, the conventional digital echo canceller and analog echo canceller (DEC+AEC) solution faces challenges with high quantization noise due to the need for high-bandwidth and high-resolution digital-to-analog converters (DACs) for echo cancellation, which is costly and limits the signal-to-noise ratio (SNR) and system performance.
Innovation Solution
A transceiver with an echo cancellation apparatus that divides the echo reference signal into two parts, one processed in the analog domain and the other in the digital domain, using a slicer, digital-to-analog converters, and subtractors to reduce the dependence on high ENOB DACs, thereby avoiding saturation and improving echo cancellation performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-bandwidth and high-resolution DAC is used for echo cancellation in the analog domain, then echo cancellation performance is improved, but hardware cost and complexity increase significantly
Solution Approach 1:
The patent divides echo cancellation into two separate domains: analog domain cancellation for strong echo signals and digital domain cancellation for residual echo signals. This segmentation allows each domain to use appropriately scaled hardware, avoiding the need for a single high-performance DAC to handle all cancellation requirements.
Solution Approach 2:
The patent applies different cancellation strategies to different signal components based on their characteristics. Strong echo signals that would cause ADC saturation are cancelled in the analog domain using a lower-resolution DAC, while weaker residual echoes are handled in the digital domain with higher precision processing.
2Object-affected harmful factors
If a high-bandwidth and high-resolution DAC is used for echo cancellation, then quantization noise is reduced, but the system becomes more expensive and less practical
Solution Approach 1:
The patent segments the noise reduction function between analog and digital domains. The analog domain handles the most critical noise reduction for strong signals using a practical, lower-resolution DAC, while the digital domain provides additional noise reduction for residual signals, achieving overall low quantization noise without requiring an expensive high-resolution DAC throughout the system.
3Reliability
If analog echo cancellation is used to avoid ADC saturation, then the receive signal level is reduced, but high quantization noise from the DAC degrades SNR
Solution Approach 1:
The patent segments the signal processing into analog and digital domains with a hybrid architecture. The analog domain performs initial echo cancellation to prevent ADC saturation using a lower-resolution DAC, while the digital domain performs additional cancellation to reduce quantization noise effects, achieving both saturation avoidance and acceptable SNR performance.
Data Source
AI summary
An echo cancellation method and a transceiver to reduce dependence of a system on an enob of a DAC, and improve performance of echo cancellation. The transceiver includes an echo cancellation apparatus, a transmit link, a receive link, and a hybrid circuit. The transmit link and the receive link are coupled to a transmission line by using the hybrid circuit. The echo cancellation apparatus includes a first signal converter, a slicer, a first subtractor, a second digital-to-analog converter, a second subtractor, and a third subtractor.