1 仪器组成及工作原理1.1 仪器组成本文所用调制型脉冲超声Doppler血流检测仪主要由三部分组成,即主机部分、记录部分及Doppler信号处理与频谱分析部分。其主要技术指标是,工作频率:5.0±0.000002MHz,辐射声强:连续正弦波小于8.0mW/cm~2,调制脉冲波小于2.0mW/cm~2;调制脉冲频率,为7.5kHz;空间采样尺寸,1.0～15.0mm可调;空间采样分辨率,1.5～2.0mm;可测深度,0.0～8.0±0.1cm;诊断深度,连续波0.0～3.0cm,脉冲波0.4～3.0cm; 1 instrument composition and working principle 1.1 instrument components modulation pulse ultrasonic Doppler blood flow detector used in this article is mainly composed of three parts, namely the host part, the recording part and Doppler signal processing and spectrum analysis part. Its main technical specifications are: working frequency: 5.0 ± 0.000002MHz, radiation intensity: continuous sine wave less than 8.0mW / cm ~ 2, modulation pulse wave is less than 2.0mW / cm ~ 2; modulation pulse frequency is 7.5kHz; spatial sampling Size, 1.0 ~ 15.0mm adjustable; spatial sampling resolution, 1.5 ~ 2.0mm; measurable depth, 0.0 ~ 8.0 ± 0.1cm; depth of diagnosis, continuous wave 0.0 ~ 3.0cm, pulse wave 0.4 ~ 3.0cm;