在中红外波段通过AgGaS_2降频变換产生可调微微秒脉冲

在差频情况下,一台Nd:YAG锁模激光器和一台行波染料激光器在AgGaS_2晶体里混频,生产微微秒脉冲。染料激光器在1200～1460nm之间是可调的。最后得到的参量脉冲可调波段为3.9～9.14μm。频谱带宽是相当窄的。测量值为△v=6.5cm^(-1),该值在整个测量范围内为一常数。百分之几的Nd:YAG激光光子转换为红外光子。21ps的泵浦脉冲产生8ps参量脉冲。

MRFIC1502在GPS接收器中的应用

首先,介绍全球定位系统(GPS)接收器的结构和摩托罗拉公司生产的射频降频变换器MRFIC1502,给出用MRFIC1502设计GPS接收器的硬件连接图。然后,分析该接收器的射频输入、中频滤波、锁相回路和采样时钟等部分的工作原理,指出印制电路板设计中要注意的问题。

Study of Software Radio Receiver Development Platform

The Paper introduces an IF software radio receiver development Platform based on high-speed monolithic A/D Converter AD6640, Programmable Digital Down-converter AD6620 and high-speed DSP chip TMSC320C6701. The implementation method is described as well as AD6620 parameter setting analysis. It also presents a flow chart of the on-line programming with the help of PC. The algorithm for demodulation AM signal is discussed.