Research On Key Technique Of Micro-delay Signal Process And Its Implementation Based On CPLD

Micro-delay signal processor uses the character of transmission delay in nor gate to measure time interval, thus calculating the time delay. It has the advantages of high accuracy, low silicon square consumption and low design difficulty. It can be used in various industrial occasions.Thesis introduces the basic principle of micro-delay signal processor at the beginning. After consulting and digesting advanced micro-delay signal processor technique at home and abroad, an nor gate oscillate delay system is put forward to realize both hardware and software functions and could be used in the design of industrial ultrasonic flowmeter as well as calorimeter. Considering that nor gate oscillate delay method should be suitable for different industrial occasions, thesis mainly discusses and solves those following problems.The suitable occasion: distinguish rate of micro-delay signal processor system in thesis reaches 250ps and time measure period reaches 9999s. Since the system is based on CPLD, it can be adjusted to fit different industrial occasions, which will help reduce system cost.The distinguish rate, stability and reliability: nor gate delay method is used to improve distinguish rate of system; auto filter method is adopted to remove the measure fault and to improve system stability; CPLD integration design is used to enhance system's integration and reliability.The accuracy and measure range of system: system adopts time adjust technique to adjust the frequency flow caused by the change of temperature. The length of accumulator is increased to broaden measure range and meet needs.System consumption: Low consumption CPLD device is used to decrease hardware consumption; Oscillate measure circuit will quit work as soon as time delay measure and adjust measure stop. Working frequency and low consumption mode will be set automaticly to decrease software consumption.The micro-delay signal processor method is used in industrial flowmeter and calorimeter. After a lot of testing, the system still runs stably and has high accuracy in broad measure range. It proves the reliability, stability and practicability of system. As well, the anticipate goal is achieved.