High-Speed Data Sampling Based on FPGA and Its Application in Flowmeter

The measurement principle and hardware structure of a new-style time-difference method ultrasonic flowmeter are presented. Software arithmetic based on FPGA high-speed data sampling technology is put forward. Sample speed is up to 80 MHz and sample depth is 1 K byte, it can fulfill the requirement of ultrasonic flowmeter software arithmetic to sampling. The design can upgrade on-line. Thus, system's whole performance is improved.

I. Instruction

Data sample technology is an important composition part of intelligence meter and control instrument. It includes signal process, A/D conversion, data memory and control timing sequence logic circuits and so on. Usually these circuits are made up of some separate devices, but when the system requires high-speed data sample, since separated device's integration is low, these devices are highly difficult to match in speed. The design selects FPGA device EPIK30TI144 that possesses ten thousands logic gates and embedded array block (EAB), data buffer, address generator, reading and writing control timing sequence logic and encoding circuits in data sampling circuit are all integrated in one FPGA chip. In virtue of FPGA high-speed, large-scale characteristics, design difficulty is greatly reduced and data sampling system's integrity and reliability are improved. Moreover, FPGA can realize logic reconstruction and in-system program (ISP). So the system possesses the merits that upgrade is easy and development cycle is short.