echo attenuation

The size, edge, shape, internal echo, mass drive aspect ratio, pone attenuation and blood flow condition of the lesions were recorded. The nature of the breast lesions was analysed and judged.

并记录病灶的大小、形态、边缘、内部回声、肿块纵横经之比、后方衰减及血流情况，并对其进行综合分析来评价病灶的良恶性。

Group delay distortion, attenuation distortion and echo will cause the intersymbol interference.

影响数据传输质量的主要因素为：群时延失真、衰减失真以及回波引起码间干扰；

Based on a certain pattern, this paper discusses the design guide line and concrete implementation scheme of a general-purpose PD missile header target simulator. Some pivotal techniques are emphasized, including broad-band receiving, SSB modulation of video-frequency echo, and high precision power attenuation.

叙述了基于某型PD导引头的通用目标模拟器的设计思路和具体实现方案，着重介绍了系统中所应用的宽带接收、视频回波的单边带调制和高精度功率衰减技术。

Pulse-echo based ultrasonic attenuation model for porosity test of carbon fiber composites

碳纤维复合材料孔隙率的脉冲反射法超声衰减测试模型