For requirements of working power consumption and high realtime performance of self-contained ocean current meter

a digital processing system of self-contained acoustic ocean current meter with an architecture of microprocessor plus field programmable gate array（ FPGA）

is designed

in which low power consumption processor achieves system level task maintenance and power management

and FPGA module fulfills realtime ocean current measurement adopting multiple correlation frequency measurement algorithm. Also

software-hardware interface between the microprocessor and the FPGA is designed to guarantee realtime data communication. Experimental results are given: the error of system is less than 0. 94 % in environment with signal to noise ratio（ SNR） of 10 d B

and power consumption is low

which is only 19 m W standby and 167 m W operating power consumption.