Multi-Voltage Threshold Digitization Method

Analog-to-digital converters (ADCs) transform the analog signals of time-variant physical quantity into digital signals for storing and processing. As the bridge between natural science and information science, ADCs are indispensable in modern industry and scientific research. Since the 1920s, uniform time-domain sampling has become the basic principle in the field of ADCs with the establishment of its electronic implementation and mathematical theory. In the following decades, applications such as positron emission tomography (PET), nuclear fusion neutron spectrum, neutrino detection, etc., which require sampling of many high-speed signals, have emerged one after another. In these applications, ADCs based on uniform time-domain sampling show disadvantages of high power consumption and high cost, so the signal has to be pre-processed before digitalization with losing the original information of the signal. Based on value-domain sampling, the Multi-Voltage Threshold (MVT) method digitizes the signal through several voltage thresholds and then reconstructs the signal with a computer using prior information. The MVT method makes it possible to accurately digitize a large number of high-speed signals. At present, the MVT method has been applied in PET, X-ray security inspection, neutron logging, proton therapy monitoring, etc. This paper outlines the principle of the MVT method, introduces the research progress of MVT electronics in recent years, and further provides an outlook of the MVT research trend.