Joint Transmit Receive Image Compensation Blind Adaptive Calibration
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Solution Overview
Problem
Transceiver systems face challenges with image rejection, where inverted signals appear on opposite sides of the local oscillator frequency during transmission and DC when receiving, and existing image compensation techniques require offline calibration or are limited to receive-only systems.
Innovation Solution
A joint transmit/receive image compensation system employing a blind adaptive calibration circuit that dynamically adapts both receive and transmit image compensation coefficients online by switching between receive and transmit modes, using a calibration controller to couple signal paths and adapt coefficients based on live signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If offline calibration is used to determine image compensation coefficients, then manufacturing precision of image compensation is improved, but loss of time occurs due to requiring transceiver to be offline
Solution Approach 1:
The patent transforms the static offline calibration process into a dynamic online calibration process. The calibration controller continuously updates image compensation coefficients while the transceiver operates, allowing the system to adapt to changing conditions without interruption. This is achieved by injecting calibration tones during operation and processing the responses to recalculate coefficients in real-time.
Solution Approach 2:
The patent performs preliminary calibration actions by pre-determining the calibration tone sequences and response measurement procedures before actual calibration execution. The system prepares calibration patterns and expected response characteristics in advance, enabling rapid coefficient updates during online operation without requiring extensive real-time computation.
2Adaptability or versatility
If blind adaptive calibration is used for receive-only systems, then adaptability is improved, but device complexity increases when extending to transceiver systems
Solution Approach 1:
The patent creates a universal calibration system that handles both transmit and receive image compensation through a single calibration controller and shared signal path. The same calibration infrastructure serves dual purposes: calibrating receive image rejection during receive modes and calibrating transmit image rejection during transmit modes, eliminating the need for separate calibration systems for each function.
Solution Approach 2:
The patent merges the transmit calibration and receive calibration processes into a unified online calibration framework. By combining the calibration tone injection, response measurement, and coefficient calculation into a single integrated process that operates during both transmit and receive modes, the system reduces overall complexity compared to maintaining separate calibration mechanisms.
3Reliability
If online calibration is implemented for continuous adaptation, then reliability is improved, but device complexity increases compared to offline calibration
Solution Approach 1:
The patent implements a self-service calibration system where the transceiver calibrates itself during normal operation. The calibration controller automatically injects calibration tones, measures the system response, calculates updated coefficients, and applies them without external intervention. This self-calibrating capability maintains reliability through continuous adaptation while minimizing the need for external calibration equipment or manual intervention.
Solution Approach 2:
The patent establishes a feedback loop where the calibration system continuously monitors the transceiver's actual image rejection performance through measured calibration tone responses and automatically adjusts compensation coefficients to maintain optimal performance. This closed-loop feedback mechanism ensures continuous reliability by adapting to drift and environmental changes without requiring external control.
Data Source
AI summary
Joint transmit/receive image compensation is performed with the transceiver online and on an ongoing basis by using blind image compensation techniques when in a receive mode in order to converge receive image compensation coefficients based on “live” receive data and then in a transmit mode, after convergence of the receive image compensation coefficients, coupling the “live” transmit signal to the receive signal path to adapt the transmit image compensation coefficients.