RF Receiver Self-Test Signal Circuit for SSB Radar Calibration
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Solution Overview
Problem
Existing Built-In-Self-Test (BIST) solutions for automotive radar sensors, particularly those using loop-back concepts, face challenges in generating suitable test signals for calibrating radar sensor ICs, as conventional Double-Side Band (DSB) signals are not adequate for high-frequency applications, leading to inaccuracies in target detection and hardware fault monitoring.
Innovation Solution
A method and circuit for generating a self-test signal by applying frequency division to a local oscillator signal, using a combination of oscillators with coarse and fine tuning, and a Phase-Locked Loop (PLL) circuit to produce a frequency-divided signal that monitors and controls the generation of the self-test signal, enabling the creation of a Single-Side Band (SSB) signal suitable for radar sensor calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional Double-Side Band (DSB) signal is used for BIST in loop-back architecture, then the test signal can be generated with simple circuitry, but the signal is not suitable for calibrating radar sensor IC and leads to inaccuracies in target detection
Solution Approach 1:
The patent transforms the test signal from a conventional DSB modulation format to a Single-Side Band (SSB) signal by changing the signal generation parameters. This involves modifying the local oscillator frequency relationships and signal mixing parameters to produce an SSB signal that is suitable for radar sensor calibration, thereby improving measurement precision while maintaining circuit feasibility
Solution Approach 2:
The patent introduces an intermediary signal processing stage that converts the locally generated test signal into an SSB signal format. This intermediary transformation layer acts as a mediator between the simple loop-back architecture and the requirements for accurate radar calibration, enabling both circuit simplicity and measurement precision
2Measurement precision
If frequency division is applied to the local oscillator signal to monitor and control self-test signal generation, then the accuracy of radar sensor performance is improved, but the device complexity increases due to additional circuit blocks
Solution Approach 1:
The frequency-divided local oscillator signal serves multiple functions simultaneously: it acts as a reference signal for generating the SSB test signal, provides a monitoring signal for verifying oscillator operation, and enables calibration of the radar sensor IC. This multi-functionality reduces the need for separate circuit blocks, thereby limiting the increase in device complexity while achieving improved measurement precision
Solution Approach 2:
The patent implements a feedback mechanism where the frequency-divided local oscillator signal is used to monitor and control the self-test signal generation process. This feedback loop ensures accurate frequency relationships are maintained, improving radar sensor performance accuracy while using the same signal for multiple purposes to minimize additional circuit complexity
3Reliability
If a Single-Side Band (SSB) signal is generated for radar sensor calibration, then the suitability for calibration and target detection is improved, but the signal generation requires more complex oscillator control and frequency division
Solution Approach 1:
The patent segments the signal generation process into distinct stages: a first oscillator generates the carrier frequency, frequency division produces an intermediate frequency signal, and a second oscillator generates the SSB modulated test signal. This segmentation allows each stage to be optimized independently, improving calibration reliability while managing the overall complexity through modular design
Solution Approach 2:
The patent employs dynamic frequency control where the local oscillator frequency is adjusted based on the desired test signal characteristics. The frequency division ratio and oscillator tuning are dynamically adapted to generate the appropriate SSB signal for different calibration scenarios, enabling reliable calibration while using dynamic parameter adjustment rather than fixed complex circuitry
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
This approach improves the accuracy of radar sensor performance by generating a suitable self-test signal for calibration, enhancing target detection and hardware fault monitoring, particularly in high-frequency applications, and aligns with safety standards like ISO 26262 by providing stable and reliable calibration data.
Implementation Method 1
applying frequency division to a local oscillator signal of a radio-frequency receiver, producing a frequency-divided signal
Implementation Method 2
a Phase-Locked Loop (PLL) circuit to produce a frequency-divided signal that monitors and controls the generation of the self-test signal
Implementation Method 3
a local oscillator signal is generated for mixing with a reception signal
Data Source
AI summary
A radio-frequency receiver includes built-in-self-test (BIST) circuitry which generates a self-test signal. A local oscillator signal is divided. A self-test oscillation signal is generated, based, at least in part, on the frequency-divided local oscillation signal. The self-test signal is generated based on the self-test oscillation signal. The BIST circuitry includes a divider, which divides the self-test oscillation signal. The frequency-divided local oscillation signal and the divided self-test oscillation signal are used to perform one or more of generating the self-test oscillation signal and controlling the generation of the self-test oscillation signal. The radio-frequency receiver may be an automotive radar receiver.