Total Process Instrument System Design And Speed Of The Algorithm Simulation Study

This article focus on the following main points: the working principle ofthe speed log, system constitution and the algorithm of velocity measurement.The log system is composed of velocity sensor, matching circuit, transmittersystem, receiver system and signal processing units. The transmitterincludes the following three functional modes: the circuit of generating sinepulse signal based on DDS, the differential amplifier circuit, the matchingcircuit of the output terminal of transmitter's electrical signal and theUltrasonic Transducer. The receiver includes differential amplifier circuitand envelope demodulation circuit. In Data-processing part, envelope of echofrom 0.5s/is specific flow layer is sampled, then the sampled signal isprocessed by MCU, ship sail speed is calculated, validity judgement is made,the next sampling time is estimated. This article takes a research on theprinciple of cross correlation algorithm, difference algorithm and improveddifference algorithm in the algorithm part. Simulation and error analysisin velocity measurements is presented at the end.