YAN Yu, CHEN Shi-li, ZENG Zhou-mo
（State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, China）
Abstract： The acoustic Doppler current profilers (ADCP) as a new type of flow measuring equipment, can measure the flow velocity of the channel section directly. ADCP has the advantages of short measuring time and wide measuring range. The traditional ADCP processing system uses analog method to realize demodulation and filtering, which will introduce extra errors. While digital processing system will greatly increase the computation and slow down the speed of data processing. To solve this problem, an efficient real-time broadband ADCP digital signal processing system is proposed based on the low computational cascade integrator comb (CIC) cascade and interpolated second-order polynomial (ISOP) filter banks. The digital in-phase and quadrature (IQ) demodulation, CIC filter banks, and complex autocorrelation operation steps are cascaded with a pipelined method in the system, which greatly improves the system operating speed while avoiding the high memory occupation of non-real-time systems.
Key words： acoustic Doppler current profilers (ADCP)； in-phase and quadrature (IQ) demodulation； cascade integrator comb (CIC)； interpolated second-order polynomial (ISOP)； autocorrelation operation
CLD number： TB565.4 Document code： A
Article ID： 1674-8042（2019）02-0116-10 doi： 10.3969/j.issn.1674-8042.2019.02.003
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基于CIC滤波器组的宽带ADCP数字回波处理
闫宇， 陈世利， 曾周末
（天津大学 精密测试技术与仪器国家重点实验室， 天津 300072）
摘要： 声学多普勒流速剖面仪（ADCP）作为一种新兴的测流设备， 可以直接测量河面剖面流速， 具有测量时间、 范围广等优点。 传统的ADCP处理系统在模拟解调滤波处理的过程中会引入额外误差， 而数字的处理系统会大幅加大运算量， 影响数据处理速度。 在低运算量的CIC级联及ISOP滤波器组的基础上， 提出了高效的实时宽带ADCP数字回波处理系统。 系统将IQ解调、 CIC滤波器组和复自相关运算步骤采用流水线的方式级联， 大幅提升了系统运行速度的同时避免了非实时系统的大量FIFO占用。
关键词： ADCP； IQ解调； CIC； ISOP； 复自相关运算
引用格式：YAN Yu, CHEN Shi-li, ZENG Zhou-mo. Broadband ADCP digital signal processing based on CIC filter banks. Journal of Measurement Science and Instrumentation, 2019, 10（2）： 116-125. ［doi： 10.3969／j.issn.1674-8042.2019.02.003］
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