high-frequency selectivity 中文意思是什麼
high-frequency selectivity
解釋
高頻選擇法- high : adj 1 高的〈指物，形容人的身高用 tall〉；高處的；高地的。2 高級的，高等的，高位的，重要的。3 高尚...
- frequency : n. 1. 屢次，頻仍，頻繁。2. （脈搏等的）次數，出現率；頻度；【物理學】頻率，周率。
- selectivity : n. 1. 選擇；精選。2. 【無線電】選擇性；選擇度；【物理學】選擇能力；選擇率。
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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。 -
The millimeter wave diplexers used in the ka - band satellite communications are investigated. these diplexers are of high working frequency, narrow passband and high selectivity, which demands the channel filters good performance
所研究的毫米波雙工器工作頻率高（接近40ghz ） ，收發通道帶寬窄、接收頻率和發射頻率間隔很小。 -
Much attention has been paid to it, because the system can achieve better performance than conventional cdma in high data applications and it is potentially robust to channel frequency selectivity
Cdma技術和ofdm技術結合產生了多載波cdma系統，它很好地解決了高速數據業務下傳統cdma系統性能下降等一系列問題。
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