RC-CR Phase Calibration Circuit for Measurement Receiver Accuracy
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Solution Overview
Problem
Measurement receivers in wireless communication systems face challenges in maintaining accurate phase difference between RC and CR paths due to mismatched loading impedance and layout variations, leading to RC-CR phase errors that affect calibration performance.
Innovation Solution
A circuit with a RC-CR phase error calibration mechanism, utilizing an array of capacitors and switches connected in parallel, adjusts the phase difference between output signals to fall within a predetermined range by controlling the switches, ensuring accurate phase shift across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If RC-CR circuit is used for phase shifting in measurement receiver, then phase shift function is achieved, but phase accuracy deteriorates due to mismatched loading impedance and layout variations
Solution Approach 1:
The patent applies preliminary action by performing phase error calibration before actual measurement operations. A calibration mode is implemented where test signals are processed through the RC-CR circuit to determine phase errors, which are then compensated for during normal receiver operation. This pre-calibration approach eliminates phase inaccuracies caused by impedance mismatches and layout variations before they affect measurements.
Solution Approach 2:
The patent implements feedback mechanisms where the phase error detection unit continuously monitors the phase difference between RC and CR paths. The detected phase errors are fed back to adjust the receiver's signal processing, enabling real-time compensation. This closed-loop feedback system maintains phase accuracy despite variations in loading impedance and circuit layout.
2Device complexity
If fixed capacitor values are used in RC-CR circuit, then circuit simplicity is maintained, but phase error calibration capability is limited
Solution Approach 1:
The patent transforms the static, fixed capacitor design into a dynamic system where capacitor values can be adjusted during calibration. Switches are introduced to connect different capacitor values to the RC-CR circuit, enabling the circuit to adapt its characteristics. This dynamic configuration allows phase error calibration while maintaining reasonable circuit simplicity through systematic switching arrangements.
Solution Approach 2:
The patent segments the capacitor configuration into multiple discrete values that can be selectively activated. Instead of using a single fixed capacitor, the circuit employs multiple capacitors with different values, each可控 through switches. This segmentation enables precise phase error calibration by selecting appropriate capacitor combinations while keeping the overall circuit structure manageable through modular organization.
3Measurement precision
If RC-CR phase error calibration is implemented, then phase accuracy is improved, but device complexity increases due to additional components
Solution Approach 1:
The patent implements multi-functionality by designing the calibration circuit to serve multiple purposes. The same RC-CR circuit structure is used both for normal signal processing and for phase error calibration. The calibration mode leverages existing circuit components rather than adding completely separate calibration hardware, thereby improving phase accuracy while minimizing the increase in device complexity.
Solution Approach 2:
The patent applies self-service by enabling the measurement receiver to perform its own phase error calibration using internal test signal generation and processing. The receiver uses its own RC-CR circuitry to detect and compensate for phase errors without requiring external calibration equipment. This self-calibration capability improves phase accuracy while avoiding the complexity of external calibration systems.
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
The solution effectively calibrates RC-CR phase errors, enhancing the accuracy of phase shift and improving the performance of measurement receivers in factory and live mode calibrations, particularly for FD I/Q image calibration in wireless communication systems.
Implementation Method 1
a RC-CR circuit, configured to phase-shift an input signal received at an input node of the RC-CR circuit, wherein the RC-CR circuit has a first output node outputting a first output signal over a first output path, and the RC-CR circuit has a second output node outputting a second output signal over a second output path
Implementation Method 2
a first circuit coupled to the RC-CR circuit at the first output node over the first output path, wherein the first circuit comprises an array of capacitors coupled in parallel and a plurality of switches, a first terminal of each of the array of capacitors is coupled to the first output node of the RC-CR circuit, and a second terminal of each of the array of capacitors is coupled to a ground of the circuit through a corresponding switch in the plurality of switches
Data Source
AI summary
A circuit includes a RC-CR circuit and a second circuit. The RC-CR circuit outputs a first signal at a first output node over a RC path, and a second signal at a second output node over a CR path. The second circuit is coupled to the RC-CR circuit at the first output node over the RC path. The second circuit includes an array of capacitors coupled in parallel and a plurality of switches, and each of the array of capacitors is connected, in series, to a corresponding switch in the plurality of switches. Each of the array of capacitors and its corresponding switch are coupled between the first output node and a ground. The plurality of switches is switched on or off such that the first signal and the second signal have a phase difference that falls within a predetermined phase range.