用于QPSK载波恢复的宽带平方电路设计

介绍采用微波混频器的上变频特性实现宽带平方电路的设计方法与具体实现,主要用于高码速率QPSK信号的载波恢复。重点考虑了平方电路的宽带设计,进行了理论推导,并给出了测试结果。采用了功分器、混频器一体化的设计思路,将二者集成在同一基片上,实现了电路的轻小型化。经测试,该平方电路在输入频率为400~800 MHz,输出频率为800~1600 MHz的频带内变频损耗平坦度为±1 dB,能使码速率为300 Mbps的QPSK信号无失真的通过。

Broad-band Square Circuit Design for Demodulation of QPSK Signal

An introduction of the design and implementation of a broad-band square circuit is given,which is used to recover the carrier of the high speed QPSK signal.Integrated circuit of the power divider and the mixer are adopted to realize the miniaturization.The test result shows that when input frequency covers the band of 400MHz-800MHz,the flatness of conversion loss is 1 dB which permit the QPSK signals that has a data rate up to 300Mbps pass through without distortion.