鎖步頻帶 的英文怎麼說
中文拼音 [suǒbùbīndài]
鎖步頻帶
英文
locking band-
By making full use of favourable narrow - band tracing filter character of pll and by combining the merits of dds such as super fine frequency resolution 、 high frequency accuracy 、 very fast frequency hoping with it, the pll / pll + dds frequency synthesizer presents wide band high quality source and super small frequency hoping step. while the electronically tuned filter abates the image interference and notably improves the selectivity. the theorem of frequency synthesizer and center - frequency - fixed filter is simply but adequately introduced first in this paper
課題中所採用的pll或dds pll鎖相頻率合成方法充分發揮鎖相環良好的窄帶跟蹤濾波特性，並結合dds的高頻率解析度、高頻率精確度和高速頻率捷變等優點，分別實現了系統所要求的高質量寬帶本振源和小步長頻率捷變；採用電調諧選頻技術，則大大改善了接收機的選擇性和抗干擾能力。In this system two oscillator are used for mixing. pll for high local oscillator and dds + pll for low local oscillator. by making full use of favourable narrow - band tracing filter character of pll and by combining the merits of dds such as super fine frequency resolution, high frequency accuracy, very fast frequency hoping with it, the pll / pll + dds frequency synthesizer presents wide band high quality source and super small frequency hoping step
系統採用兩次混頻，其中高本振的設計採用pll鎖相環頻率合成來實現，充分發揮了鎖相環頻率合成器的優良特性，實現了系統所要求的高質量寬頻帶本振源；低本振採用pll + dds頻率合成來實現，結合pll優良的鎖相特性與dds的高頻率解析度、高頻率精確度等優點，實現了頻率的小步進高精度合成。Since commercial pll ic came out, phase - locked - loop frequency synthesis has become widely accepted. but when narrow frequency - step is required, the loop bandwidth has to decrease while cannot meet the demand of frequency - hopping speed
數字鎖相集成器件出現以來，鎖相式頻率合成器得到迅速發展，但是當需要窄頻率步進時，環路帶寬需要降低，致使鎖定時間變長，不能滿足快速跳頻的要求。
分享友人