very low frequency band 中文意思是什麼

very low frequency band 解釋
甚低頻波段
  • very : adv 1 〈用於修飾形容詞、副詞或分詞〉很，甚，頗，極，非常。2 〈與否定詞結合〉（不）怎樣，（不）大...
  • low : adj 1 低的；淺的，矮的。 low flight 低飛。 a low temperature 低溫。 low tide [water] 低潮。 The g...
  • 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。
  • band : n 1 帶，繩；帶形物；箍；箍條；嵌條；鑲邊；鋸條； 〈pl 〉 （法官等的）寬領帶。2 束縛，羈絆；義務；...
  1. 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。
  2. Very - low frequency band

    甚低頻頻帶
  3. The developments and applications of the low frequency ultra wide band ( uwb ) sar system are very important for military affairs

    低頻超寬帶（ ultrawideband ， uwb ） sar的研究與應用具有重要的軍事意義。
  4. The technology of very low bit rate for hf ( high frequency ) communication means that, one technology of ecm ( electronic counter measures ) resistant communication is developed for low bit data message exchange in the time of battle which data communication is destroyed by electronic disturber. it is regarded by armies in the battle of information, because that it can overcome the very low snr ( signal noise ratio ), very high narrow - band interference and multipath with maxium delay of fifty millisecond

    短波最低限度通信技術是在戰時強電磁干擾情況下能實現保證最低限度的數據報通信的一種抗干擾通信技術。由於其能有效的克服極低信噪比、較強的窄帶干擾和幾十毫秒的多徑，在信息戰中受到各軍高度重視。
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