Radar Phase Shifter Self-Diagnosis Using PLL Signal Reuse
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Solution Overview
Problem
Existing millimeter-wave radar systems face challenges in self-diagnosis due to the complexity of phase shifter calibration and the need for multiple PLLs, which increases costs and reduces accuracy in phase evaluation.
Innovation Solution
A self-diagnosis signal generation unit utilizing a general-purpose multi-channel IC generates a self-diagnosis clock signal and output signals with high correlation, allowing for on-chip BIST signal source generation without additional PLLs, and uses a combination of IQ signal generators, mixers, and adder circuits to produce a one-tone signal for phase evaluation, suppressing image interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple PLLs are used for self-diagnosis in millimeter-wave radar systems, then frequency accuracy can be maintained, but device complexity and cost increase
Solution Approach 1:
The patent makes the existing local oscillation signals serve dual purposes: both for normal radar operation and for self-diagnosis. The local oscillation signals generated by the PLLs are reused as reference signals for phase evaluation, eliminating the need for separate diagnosis PLLs while maintaining frequency accuracy
Solution Approach 2:
The patent combines the self-diagnosis function with the existing signal generation infrastructure. By merging the diagnosis signal source with the operational local oscillation signals, the system achieves phase evaluation capability without adding separate PLL circuits, thus reducing device complexity
2Measurement precision
If phase shifter calibration is performed using conventional methods, then phase evaluation can be achieved, but the process becomes complex and time-consuming
Solution Approach 1:
The patent performs phase evaluation by comparing the phase of received signals with the known phase of local oscillation signals before final target detection. This preliminary phase characterization enables faster subsequent diagnosis operations and reduces the time needed for accurate phase evaluation
Solution Approach 2:
The system uses its own operational local oscillation signals to perform self-diagnosis of phase shifters, eliminating the need for external calibration equipment. The radar system diagnoses itself using resources already available during normal operation, reducing both time and complexity
3Measurement precision
If additional PLLs are added for BIST signal generation, then frequency accuracy is maintained, but manufacturing cost increases
Solution Approach 1:
The patent makes the existing PLL-generated local oscillation signals serve dual purposes: both for normal radar operation and for BIST signal generation. This eliminates the need for additional dedicated PLLs for testing, reducing manufacturing cost while maintaining frequency accuracy through the reuse of already-p precision-generated signals
Data Source
AI summary
A self-diagnosis device of a radar system or a phased-array antenna module including a general-purpose multi-channel IC and a transmission phase shifter IC having a plurality of transmission output terminals and reception terminals is configured to perform a self-diagnosis of the transmission phase shifter by utilizing a signal that is generatable by the general-purpose multi-channel IC, which is enabled by a built-in self-test circuit that (A) generates a self-diagnosis monitor signal converted into a low frequency band, which is a mixture of (i) a self-diagnosis signal generated from (a) a third output signal and a fourth output signal output in sync from same PLL with (b) a first output signal to be supplied to a reception frequency converter of the general-purpose multi-channel IC, and (ii) a composite signal of the transmission channel, and (B) analyzes a phase of the self-diagnosis monitor signal.