3 . with comprehensive improvement of transponder including structural adjustment to lna ; optimization of ( phase locked loop ) pll filter ; structural adjustment to the transmitter and phase error adjustment to the intermediate frequency demodulation circuit , we have successfully enhanced sensitivity , expanded dynamic range , increased transmitting power and improved the spectrum purity ; decreased capture time for pll ; improved the signal quality after demodulation ; reduced its volume and power consumption . 4 3 、對(duì)通信機(jī)的全面改進(jìn),包括lna結(jié)構(gòu)的調(diào)整、鎖相環(huán)環(huán)路濾波器的優(yōu)化、發(fā)射部分結(jié)構(gòu)的調(diào)整以及中頻解調(diào)電路的相差調(diào)整,提高了系統(tǒng)的接收靈敏度、改善了本振的頻譜純度、減少了鎖相環(huán)的鎖定時(shí)間、使中頻解調(diào)后的信號(hào)質(zhì)量大為提高,同時(shí)還減少了體積、節(jié)約了系統(tǒng)的功耗。