Peak-Interrupt ADC Circuit for Overlapping Photon Pulses
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Solution Overview
Problem
Existing photon counting CT systems face challenges in accurately counting radiation photons due to pileup phenomena, where multiple pulses overlap, requiring multiple capacitors and increasing circuit complexity.
Innovation Solution
A signal processing circuit that interrupts A/D conversion when a next peak is detected during conversion, allowing immediate start of the next conversion and reducing the precision of A/D conversion, thereby simplifying the circuit arrangement and improving counting performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple capacitors are used to hold signal values of multiple peaks, then counting accuracy is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic A/D conversion interruption based on real-time peak detection. When a new peak is detected during ongoing conversion, the system dynamically interrupts the current conversion and reallocates resources to process the new peak, enabling accurate handling of overlapping pulses without requiring multiple static capacitors
Solution Approach 2:
The system changes the operational parameters of the A/D converter by dynamically adjusting conversion timing and interruption points based on detected peak positions. This allows the single capacitor to be efficiently reused for multiple peaks by changing when conversions start and stop, rather than requiring simultaneous holding capability of multiple capacitors
2Productivity
If A/D conversion is interrupted early to process next peak immediately, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
The system uses the output from the interrupted A/D conversion as an initial value for the next conversion. This self-service mechanism allows the conversion process to continue seamlessly with accumulated information, maintaining precision while enabling immediate processing of the next peak without full conversion cycles
Solution Approach 2:
The system performs preliminary peak detection and timing analysis before committing to full A/D conversion. By detecting peaks early and pre-positioning the conversion process, the system can interrupt at optimal points and use partial conversion results as starting points for subsequent conversions, maintaining both speed and precision
Data Source
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AI summary
A signal processing circuit (123) includes a detection unit (126) configured to detect generation of a peak in an analog signal based on an input of a photon, an A/D conversion unit (202) configured to perform A/D conversion of a signal value into digital data of bits by determining a value of each of the bits from an upper bit to a lower bit, and a control unit (201) configured to control the A/D conversion unit so that, in a case in which the generation of a second peak of the analog signal is detected during the A/D conversion of a signal value of a first peak of the analog signal, the A/D conversion of the signal value of the first peak will be interrupted and the A/D conversion of a signal value of the second peak will be started.