Hybrid Circuit Impedance Optimization via Automated Echo Measurement
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Solution Overview
Problem
Manual impedance balancing in telephone systems to reduce echo is time-consuming, requires on-site assistance, and is difficult to differentiate between local and distant echoes, especially when dealing with multiple Foreign Exchange Office (FXO) ports.
Innovation Solution
A system and method that automatically measures echo return loss by inserting a white noise signal through an analog telephone line with selectable impedance settings, determining the optimum impedance configuration without manual reconfiguration, and applying it to the hybrid circuit interface, eliminating the need for on-site operators and automating configuration changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual impedance balancing is performed to reduce echo, then echo return loss is improved, but time consumption and operational complexity increase significantly
Solution Approach 1:
The system automatically performs impedance balancing without requiring manual operator intervention. The automated tool independently executes test calls, measures echo return loss, analyzes results, and configures optimal impedance settings, enabling the system to serve itself and eliminate time-consuming manual operations
Solution Approach 2:
The patent replaces manual mechanical operations (physical impedance adjustment, manual test call placement, manual measurement recording) with an automated electronic system that uses software control, digital signal processing, and automatic configuration interfaces to perform the same functions
2Measurement precision
If manual test calls are placed to measure echo, then echo measurement is achieved, but differentiation between local and distant echoes becomes difficult
Solution Approach 1:
The automated tool extracts and isolates the local echo component from the total echo signal by using controlled test calls and signal analysis techniques, separating the measurement of local hybrid echo from other echo sources in the communication path
Solution Approach 2:
The patent introduces an automated measurement tool as an intermediary between the operator and the echo measurement process, which systematically controls test calls and analyzes echo characteristics to identify and measure local echo separately from distant echoes
3Reliability
If multiple FXO ports are configured manually, then each port can be optimized, but the complexity and time required increases linearly with the number of ports
Solution Approach 1:
The automated tool is designed to handle multiple FXO ports through a universal interface and standardized measurement procedure, allowing the same automated process to be applied to any number of ports without increasing operational complexity, as the system automatically iterates through each port
4Ease of operation
If on-site assistance is required for manual impedance balancing, then test calls can be placed, but remote operation capability is lost
Solution Approach 1:
The automated tool enables remote operation by making the system self-sufficient for impedance balancing operations, eliminating the need for on-site personnel to place test calls or record measurements, as all operations are automatically executed and configured through remote access
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
This approach significantly reduces echo return loss, streamlining the process to optimize impedance settings, reducing operator errors, and enabling remote operation by completing impedance testing in a fraction of the time required by manual methods.
Implementation Method 1
Energy passing from the four-wire to the two-wire circuit often is reflected back into the four-wire circuit section, creating an echo
Data Source
AI summary
A system and method in accordance with a non-limiting aspect minimizes echo return loss in a communications system. The dial tone is broken on an analog telephone line connected to a hybrid circuit having selectable impedance configurations and that interfaces a digital communications circuit and the analog telephone line. A white noise signal as a test call is inserted through the hybrid circuit onto the analog telephone line corresponding to a selected impedance configuration. The returned white noise signal is used for measuring the echo return loss. The test call is dropped. This process is repeated at different impedance configurations to obtain echo return loss measurements at each of the impedance configurations. The optimum impedance setting configuration is determined based on the results and applied to the hybrid circuit and typically set during a running telephone configuration.