spectrum n. (pl. -tra ) 1.【物理学】谱,光谱;波谱;能谱,质谱。 2.【无线电】射频频谱;无线电(信号)频谱。 3.【心理学】(眼睛的)余像;残像。 4.〔转义〕范围,幅度;(连续的)系列。 an absorption spectrum 吸收(光)谱。 a bright line spectrum 线状光谱。 an optical spectrum 光谱。 a solar spectrum 太阳光谱。 a wide spectrum of opinion 意见的不同幅度甚大。
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 、对通信机的全面改进,包括lna结构的调整、锁相环环路滤波器的优化、发射部分结构的调整以及中频解调电路的相差调整,提高了系统的接收灵敏度、改善了本振的频谱纯度、减少了锁相环的锁定时间、使中频解调后的信号质量大为提高,同时还减少了体积、节约了系统的功耗。