RF Receiver Self-Test via Selective Circuit Node Injection
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Solution Overview
Problem
There is a need for RF transceivers or receivers with improved self-test capabilities to enhance the reliability of radar sensors and other wireless communication systems, particularly in applications where functional safety standards like ISO 26262 must be met.
Innovation Solution
The proposed solution involves an RF receive circuit with a mixer, an analog-to-digital converter (ADC), and a signal processing chain that includes at least two circuit nodes, along with an oscillator circuit capable of generating a test signal. This setup allows for selective feeding of the test signal into specific nodes within the signal processing chain, enabling both production and self-testing through automatic test equipment or a digital signal processor, facilitating spectral analysis for assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an RF transceiver uses highly integrated RF circuits in a single chip package, then device complexity is reduced and manufacturing is simplified, but reliability and self-test capability are worsened due to difficulty in testing individual components
Solution Approach 1:
The signal processing chain is divided into multiple discrete circuit nodes (first circuit node, second circuit node, third circuit node) that can be individually selected and tested. This segmentation allows each component section to be isolated and tested separately despite being integrated on a single chip, thereby maintaining both integration benefits and testability.
Solution Approach 2:
A test signal injection circuit is introduced as an intermediary component that can inject test signals at selected circuit nodes and extract signals from other nodes. This intermediary enables testing of integrated components without requiring external testing equipment to access internal circuit points, thus maintaining reliability while preserving integration.
2Reliability
If functional safety standards like ISO 26262 are implemented, then operational safety is improved, but device complexity and testing requirements increase
Solution Approach 1:
The RF transceiver incorporates built-in self-test functionality through the test signal injection circuit that can autonomously test its own components. The circuit can select different circuit nodes for injection and extraction, enabling the device to perform self-diagnosis and health monitoring without external testing infrastructure, thus meeting functional safety standards while avoiding increased complexity.
3Measurement precision
If multiple circuit nodes are tested individually, then measurement precision and reliability are improved, but testing time and productivity are reduced
Solution Approach 1:
The test signal injection circuit is designed with multi-functionality to perform multiple testing operations through a single unified structure. It can select different circuit nodes for signal injection and different nodes for signal extraction, allowing comprehensive testing of multiple components using one versatile testing mechanism rather than requiring separate testing circuits for each node, thus maintaining precision while improving testing efficiency.
Data Source
AI summary
A radar sensor includes a mixer configured to receive an radio frequency (RF) input signal to down-convert the RF input signal into a base-band or intermediate frequency (IF) band, an analog-to-digital converter (ADC), and a signal processing chain coupled between the mixer and the ADC. The radar sensor further includes an oscillator circuit that is configured to generate a test signal. The ADC is coupled to an output of the signal processing chain, and is configured to generate a digital signal by digitizing an output signal of the signal processing chain, the output signal being derived from the test signal. The radar sensor further includes a digital signal processing circuit coupled to the ADC downstream thereof, the digital signal processing circuit being configured to perform a spectral analysis on frequency values of the digital signal.