ADC Clock Generation for Precise Guided Wave Radar Sampling
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Solution Overview
Problem
Inaccurate distance measurements in level transmitters due to inconsistencies in timing measurements caused by variations in interrupt handling and phase jitter, leading to reduced accuracy in determining material boundaries.
Innovation Solution
A dedicated hardware analog-to-digital converter clock generator is used to generate a consistent ADC clock signal, independent of variations in interrupt handling, ensuring precise timing for sampling reflected signals and improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a microcontroller-based system is used to generate ADC clock signals, then the device complexity is reduced and ease of operation is improved, but measurement precision deteriorates due to variations in interrupt handling and phase jitter
Solution Approach 1:
The system separates the ADC clock signal generation function from the main microcontroller into a dedicated hardware module. This segmentation allows the clock signal generation to operate independently with deterministic timing, eliminating the impact of microcontroller interrupt handling variations and phase jitter on measurement precision.
Solution Approach 2:
A dedicated hardware clock generator acts as an intermediary between the microcontroller and the ADC. This intermediary component receives timing information from the microcontroller but generates the actual ADC clock signals through dedicated hardware logic, ensuring precise and consistent timing independent of software interrupt variations.
2Reliability
If interrupt handling is used in the microcontroller system, then the system is easier to implement and operate, but timing consistency deteriorates leading to reduced measurement accuracy
Solution Approach 1:
The system replaces software-based interrupt handling with hardware-based clock signal generation. The dedicated hardware clock generator uses deterministic hardware logic circuits instead of software interrupts, providing consistent and reliable timing without the variability introduced by interrupt handling and context switching.
3Measurement precision
If phase jitter is present in the clock signal, then the system is simpler to implement, but measurement precision deteriorates due to inconsistent timing
Solution Approach 1:
The clock signal generation function is extracted from the main microcontroller system into a separate dedicated hardware module. This extraction removes the source of phase jitter associated with the microcontroller's variable interrupt handling and internal clock management, providing a stable and consistent clock signal for precise timing measurements.
Data Source
AI summary
A level transmitter includes an analog-to-digital convertor clock signal generator that receives a transmitter clock signal that is used to establish when an incident signal is transmitted toward a material boundary. The analog-to-digital convertor clock signal generator uses the received transmitter clock signal to generate an analog-to-digital convertor clock signal. An analog-to-digital convertor samples an analog waveform based on the analog-to-digital convertor clock signal and generates a digital value for each sample of the analog waveform. An analysis module analyzes the digital values to determine a distance to the material boundary.