摘要:
本文采用步进转动(顺时针或逆时针)的信码作信源,分析了广义四相调制的特性,给出调制信号的频谱和两调相电路间的导纳关系表达式,计算了几种典型四相调制频谱的实例,据此可判定调制的效果和相位误差,并用于动态测试中对四相调制器进行调整,实验表明测得的结果与理论计算是相符的。本文还报道了X波段四相调制器的实验情况,测得其最大相位误差小于4,相让精度可达0.1,插入损耗小于4dB,传送数据率可达 34Mb/s。
Abstract:
Using the clockwise or anticlockwise stepping pulse code signal, the characterities of general QPSK modulation are analysed. The spectrums in several operational conditions and the admittance formulas of related two modulation circu ts are given. Several typical examples of QPSK modulation are calculated. The results are used to decide the modulation effect and phase error, and also to adjust the QPSK modulator under the dynamic testing. The experimental results are in agreement with the theortical calculations. An X band QPSK modulator is also presented. the maximum phase error is less than 4, insertion loss less than 4 dB, phase accuracy near 0.1 and transmission data rate up to 34 Mb/s.
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