Based on the principle of the ultrasonic cross - correlation flowmeter , the key factor of the development of cross - correlation flowmeter , namely the design of cross - correlator , is analyzed in the paper . digital signal processing is introduced to design the flowmeter , the cross - correlation operation of random noise signal is dealt with inside the frequency field , and the digital cross - correlator is designed 本文從超聲相關流量計的工作原理出發,分析了超聲相關流量計研制的關鍵因素,即相關器的設計,并將數字信號處理技術引入了超聲相關流量計的設計,在頻域內對流動隨機噪聲信號進行相關處理,構造了數字相關器。