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 detecting material boundaries.
Innovation Solution
A dedicated hardware ADC clock generator is used to generate a consistent ADC clock signal, independent of variations in interrupt handling, ensuring precise timing for analog-to-digital conversion and improving the accuracy of distance calculations.
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 timing system is segmented into two independent parts: a dedicated hardware ADC clock generator that produces precise timing signals, and a microcontroller that handles higher-level control functions. This segmentation allows each component to specialize in its respective function, with the hardware generator ensuring measurement precision while the microcontroller maintains ease of operation.
Solution Approach 2:
A dedicated hardware ADC clock generator acts as an intermediary component between the microcontroller and the analog-to-digital converter. This intermediary generates timing-critical signals independently of microcontroller interrupt handling, thereby eliminating phase jitter and ensuring consistent sampling timing without requiring complex microcontroller intervention.
2Measurement precision
If interrupt handling is used to trigger ADC conversion, then the ease of operation is improved, but measurement precision deteriorates due to variations in interrupt handling timing
Solution Approach 1:
The timing-critical ADC clock signal generation function is extracted from the microcontroller's interrupt handling system and placed in a dedicated hardware generator. This extraction removes the source of timing variations, ensuring that sampling occurs at consistent intervals regardless of interrupt handling variations, while the microcontroller retains simplicity in controlling the overall conversion process.
3Measurement precision
If phase jitter is present in the ADC clock signal, then the ease of manufacture is improved by using standard microcontroller components, but measurement precision deteriorates
Solution Approach 1:
The system is divided into a dedicated hardware ADC clock generator module and a standard microcontroller module. This segmentation allows the use of simple, manufacturable components while achieving high precision through the specialized hardware timing generator that eliminates phase jitter in the critical sampling clock signals.
Data Source
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AI summary
A level transmitter (500) includes an analog-to-digital convertor clock signal generator (504) that receives a transmitter clock signal that is used to establish when an incident signal is transmitted toward a material boundary (122, 124). The analog-to-digital convertor clock signal generator (502) uses the received transmitter clock signal to generate an analog-to-digital convertor clock signal. An analog-to-digital convertor (534) 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 (537) analyzes the digital values to determine a distance to the material boundary (122, 124).