Transceiver Loopback Calibration for Non-Linear Distortion
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Solution Overview
Problem
Increasing bandwidth in receivers introduces noise, reducing signal-to-noise ratio (SNR) and inducing non-linear distortions, necessitating an effective correction mechanism for transceiver devices.
Innovation Solution
A method and apparatus utilizing an internal loopback path within the transceiver device to characterize and compensate for non-linear distortion in the receiver chain, employing post distortion processing and a controlled test signal to improve SNR without external test equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bandwidth of receivers is increased to enhance data throughput, then data throughput is improved, but signal-to-noise ratio deteriorates due to additional noise
Solution Approach 1:
The patent changes the parameter of signal power level to compensate for SNR degradation. By increasing signal power in the receiver, the system counteracts the noise introduced by bandwidth expansion, thereby maintaining acceptable SNR while preserving enhanced data throughput capability
2Reliability
If power level of signal in receivers is increased to mitigate SNR degradation, then signal-to-noise ratio is improved, but non-linear distortions are induced in active components
Solution Approach 1:
The patent implements a feedback mechanism where the receiver's own transmitted signal is looped back through its receiver chain for self-testing. The measured non-linear distortion characteristics are fed back to the digital processing unit, which then applies compensation algorithms to cancel out the distortions, allowing the system to maintain high signal power while correcting the harmful non-linear effects
Solution Approach 2:
The patent converts the harmful non-linear distortions into useful calibration information. By intentionally measuring the distortions through the loopback path, the system characterizes the non-linear behavior and uses this knowledge to design compensation filters that transform the distorted signal back into a clean signal, turning the harmful effect into a benefit
3Measurement precision
If external test equipment is used to evaluate non-linear distortion, then measurement precision is improved, but hardware cost and device complexity increase
Solution Approach 1:
The patent enables the receiver to perform self-testing and self-characterization using its own transmitter chain and loopback path. The system generates test signals internally, measures its own non-linear distortion through the loopback, and processes the results without requiring any external test equipment, thereby eliminating additional hardware cost and complexity while achieving accurate distortion characterization
Data Source
AI summary
A method for calibrating non-linear distortion in a transceiver device is provided. The transceiver device has a transmitter chain and a receiver chain. The method includes: applying a test input signal from the transmitter chain to the receiver chain through a loopback path inside the transceiver device; generating a non-linear distortion model regarding non-linear behavior of the receiver chain based on a test output signal that is produced by the receiver chain in response to inputting of the test input signal; configuring a post distortion processing based on the non-linear distortion model; and performing the post distortion processing on a received signal to generate a compensated received signal.