The DDS technique is mainly described, and the basic principle and the composition of the signal simulator are introduced with a complex structure strata echo signal.
同时重点介绍了DDS技术，并以结构复杂的地层回声信号为例介绍了信号模拟器的基本原理及构成。
2
By comparison with simple shape targets, the echo strength of the complex targets versus frequency and range is more complex.
与简单形状目标相比，复杂目标的回声强度随频率和距离的变化更为复杂。
3
A complex structure signal simulator designed by DDS technique is introduced. It can simulate several kinds of strata echo waves or complex structure signals.