RF Receiver BIST Signal Generation Using Divided LO Feedback
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Solution Overview
Problem
Conventional Built-In-Self-Test (BIST) circuit architectures for radio-frequency (RF) transceivers, particularly in automotive radar sensors, face challenges in generating accurate test signals for calibration due to the complexity of high-frequency signal generation and image rejection, limiting their effectiveness in high-frequency applications like radar systems.
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 chirp modulation and accurate calibration of RF transceivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional BIST circuit architectures use additional circuit building blocks (mixer and attenuator) to inject test signals, then the test signal can be down-converted to IF signal, but the generated DSB signal is not suitable for calibrating radar sensor IC and the system complexity increases
Solution Approach 1:
The patent extracts only the essential frequency division function from the conventional complex BIST architecture, eliminating unnecessary mixer and attenuator components. The frequency-divided local oscillator signal directly controls the self-test signal generator, simplifying the circuit while maintaining calibration accuracy through precise frequency control.
Solution Approach 2:
The frequency-divided local oscillator signal serves multiple functions: it controls the frequency of the self-test signal generator, provides reference for phase-locking, and enables both calibration and fault monitoring operations. This multi-functionality reduces the need for separate dedicated circuits for each function.
2Measurement precision
If conventional BIST circuits use DSB signal injection, then the receiver input can be tested, but the signal is not suitable for radar sensor IC calibration and measurement precision is insufficient
Solution Approach 1:
The patent changes the frequency parameter of the test signal by using frequency division on the local oscillator signal. This frequency-divided signal then controls the self-test signal generator to produce signals at precisely controlled frequencies that are suitable for radar sensor calibration, improving measurement precision while maintaining operational simplicity.
3Adaptability or versatility
If multiple oscillators with separate control are used for generating local oscillator and self-test signals, then frequency tuning flexibility is achieved, but frequency stability and synchronization between oscillators deteriorates
Solution Approach 1:
The patent implements feedback by using the frequency-divided local oscillator signal to control the self-test signal generator. This feedback mechanism ensures that the self-test signal frequency remains synchronized with the local oscillator, maintaining frequency stability while allowing broad tuning ranges through the phase-locked loop's ability to track frequency changes.
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 and stability of RF transceivers by generating a Single-Side Band (SSB) signal suitable for radar sensor calibration, effectively addressing systematic and random errors, and enhancing the reliability of target detection and hardware fault monitoring in complex environments.
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
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.