very high frequency band 中文意思是什麼

very high frequency band 解釋
甚高頻波段
  • 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...
  • 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。
  • 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. 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。
  2. 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。
  3. Fem and bem is very adapted to predict the noise level in lower frequency, but they need to describe the geometry of structure detailedly which is wasting - time for many modes in system and high frequency, wide band and random variable

    有限單元方法和邊界單元方法可以較好地預示低頻環境噪聲，但需要較為詳細地描述結構的幾何特性。對于時間上是隨機的寬帶高頻分量，結構中存在大量模態的情況有時是費時的。
  4. Upstream channels cover in 5 65mhz, which is a part of the bandwidth of high frequency （ hf ） and very high frequency （ vhf ）. it is liable to incur noises ingress onto the band. since hfc system has the tree - and - branch topology between the fiber - node and subscriber units, subscriber units belonging to one fiber - node share the same upstream channel, forming the " noise funneling " effect

    上行頻帶位於5 - 65mhz之間，這一頻帶為高頻（ hf ）和甚高頻（ vhf ）的一部分，此頻帶易受噪聲干擾；此外，由於從光節點到用戶端為樹型分支結構，同一光節點的多個用戶共享同一通道，形成了漏斗效應。
  5. Over - the - horizon radar ’ s beam - frequency is high frequency band and its wavelength is so long that the annate ’ s characters are very complicated when applicated on the ship. the character of coupling between cells and the environment must be measured to compensate in the radar signal process step. the ship - based over - the - horizon radar uses cfa ( crossed field antenna ) as array antennas ’ cell

    艦載超視距雷達使用高頻信號作為發射頻率，其波長較長，在艦船有限的空間內，陣列天線的陣元之間的耦合與陣元與背景之間耦合都十分嚴重，必須測量陣列天線通道的幅相一致性，作為雷達信號處理的補償參數。
  6. Radio broadcasting systems - very high frequency, frequency modulated, sound broadcasting transmitters in the 66 to 73 mhz band ; english version ets 300750 : 1997

    無線電廣播系統.甚高頻調頻. 6至75mhz無線電廣播電臺
  7. 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。
  8. Very - high frequency band

    甚高頻頻帶
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