low frequency band 中文意思是什麼

low frequency band 解釋
低頻帶，低頻波段
  • 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. The major job is manufactured a transmitter, which has three upmixer channels. its function is to up convert the signals from c - band to ka - band. the input local oscillator is provided by a low frequency crystal oscillator which has a good performance of phase noise, through 512 times multiply to ka band. this sysetem is used in the laboratory as transmitter source of the fuze, for the multidimensional objects in practise, which lead to the complexity of the reflect signal, so the amplitude, frequency and the phase of the transmit signals both have a key role in dealing with the reflection signals. therefore, this system requires for both the coherence of the single channel ’ s amplitude, phase and multi channels

    本文的主要工作是應用戶要求製作一具有三發射通道的上變頻系統，可以將c波段的微波信號上變頻到ka波段的毫米波信號。系統的本振輸入基頻由一相位噪聲非常好的低頻率晶振提供，經過512次的倍頻放大至ka波段。本系統作為實驗室中引信的發射源，由於目標反射信號具有時變的多維性，反射信號變得極為復雜，在信號處理時，不僅信號幅值、頻率有決定意義而且相位關系也很有決定意義。
  2. Very - low frequency band

    甚低頻頻帶
  3. By using optical cable communication methods, which have advantages of great information transmission capacity, rapid velocity, wide frequency band, strong anti - jamming capability, low circuitry loss and easy construction, modern sky - wave over - the - horizontal radar can achieve information transmission and system control of full coherent radar, which has excellent abilities of security, stabilization, anti - jamming and anti - destruction

    通過採用光纖傳輸技術，利用其信息傳輸容量大，速度快，頻帶寬，抗干擾能力強，線路損耗低，易於施工等特點，實現全相參雷達的信息傳輸和系統控制，具有優良的保密性，穩定性、抗干擾性和抗摧毀能力。
  4. Parallel structure of poly - phase decomposition and parallel mixer is applied in the ddc circuit, it solves the bottleneck in mixing and increases the handle speed. the partition of the tuning channel according to the digital mixing sequence, and the ddc by means of decimating first, the low - pass filtering and mixing realize efficiently the down - conversion of the variable carrier frequency band - pass signal. according to the structure of the ddc and the requirement of the frequency

    短數據快速測頻演算法的具體實現:使用并行流水線的設計方法，提高了系統的數據吞吐率，在100mhz的系統時鐘下，能夠實時處理400mhz ~ 600mhz速率a / d采樣的數據，在64點采樣， 100mhz系統時鐘情況下，初次測頻佔用時間640ns ，以後每次測頻佔用時間縮短到160ns ，實時地提供多相濾波下變頻所需的載頻位置信息，縮短了接收機的調諧時間。
  5. Filter poly - phase decomposition method is adopted in this dissertation. the partition of the tuning channel according to the digital mixing sequence, and the digital down - conversion by means of decimating first, the low - pass filtering and mixing realize efficiently the down - conversion of the variable carrier frequency band - pass signal

    本文採用濾波器多相分解方法，按數字混頻序列劃分調諧通道，使用先抽取，后低通濾波，再混頻的數字下變頻結構，高效實現了變載頻帶通信號數字下變頻。
  6. Doing the further research on the division frequency stack on the foundation of study of predecessor, at first the residual moveout correction is done to the seismic record, make the phase axle regularity, doing foundation for the same phase stack ; then carried on division scale processing by wavelet transform ; spectrum whitening is done to each scale, the high and low frequency band need to do prolongs, the middle frequency bands only increase the value of the frequency spectrum ; several kinds of methods that estimate the value of signal - noise ratio has been studied further, and summarize their advantage and disadvantage as well as the scope of application ; the seismic record after spectrum whitening is stacked by weighting with the value of the signal - noise ratio ; then estimate the value of signal - noise ratio which is each scale section after stacking, the scale that the signal - noise ratio is big is assigned big weighting, otherwise, the scale that signal - noise ratio value is small is assigned small weight ing, and carried on weighted reconstruct to each scale section

    本文在前人研究的基礎上，在分頻疊加方面做了進一步的研究。首先對地震記錄進行剩餘時差校正，校齊同相軸，為同相疊加做好基礎工作；然後對地震記錄用小波變換的方法進行分尺度處理；對各個尺度分別做譜白化，對于高、低頻段需要做頻帶延拓，中間頻段僅提升頻譜值；對于幾種信噪比定量估計的方法進行了深入的研究，並且總結了它們的優缺點以及適用范圍；對譜白化后的地震記錄用信噪比估計值作為加權系數進行加權疊加；對于各尺度的疊加剖面也進行信噪比估計，對于信噪比大的尺度給予大的加權系數，反之，信噪比值小的尺度給予小的加權系數，對各尺度疊加剖面進行加權重構。
  7. But ridged waveguide antenna which is small in volume when working at a low frequency band can obtain a high resolution and is suitable in the rubber material measure. one of the features of the paper is that some improvements of fdtd are presented

    脊波導天線與普通金屬波導相比，在較低的頻域可以有較小的工作尺寸，因而能達到較高的解析度，且便於與同軸饋線連接，很適合用於橡膠吸收材料的測量中。
  8. Diode switches or voltage controlled varactors implement dual - band resonators such that they can offer low impedance at the second harmonic of each frequency band, while, in some cases, presenting high impedance at the fundamental frequency as an rf choke circuit

    利用二極體開關或電壓控制變容器實施雙頻共振器以提供在雙頻操作中每一個頻段之二階諧波的低阻抗，同時在一些實施例里也提供主頻段的高阻抗、兼具有射頻阻塞電路作用。
  9. But in the east, 30 ~ 60 - day low frequency propagates toward north and west and 10 ~ 20 - day low frequency spreads to south from mid - latitude as well as to east from 90 " e. 10 - 20 - day and 30 - 60 - day low frequent rain band centers, located in south china, upper - middle yangtze basins, northeast china, north china and the west part of china, are all important parts of asian summer monsoon rainfall

    東部地區， 30一60天振蕩有明顯的向北及向西傳播; 10一20天低頻降水隨位相從中緯度向南傳播，同時從90 ? e向東傳播。東部地區的10一20天和30一60天低頻雨帶中心都是東亞夏季風降水的重要組成部分，當地的夏季風降水受這兩種低頻振蕩調制。
  10. On the other hand, cdma ( code - division multiple access ) communication system has been widely considered as the mainstream of 3g communication system, because it has the good qualities such as high utilization ratio of frequency band, low transmission power, powerful anti - multiple path falling and flexible capacity

    另一方面， cdma通信系統以其高頻譜利用率、低發射功率、強抗多徑衰落特性、軟容量等優點，已被廣泛認為是第三代移動通信系統的主流。
  11. The data regression processing method based on fuzzy mathematics theory is proposed to get the middle frequency band simulating result based on finite element result of low frequency band and statistics energy analysis result of high frequency band to get a complete frequency band result and solve the middle frequency band result processing problem in the simulation of floating raft isolation system

    摘要為了解決浮筏隔振系統模擬結果的中間頻段數據處理問題，基於浮筏隔振系統低頻段的有限元分析結果和高頻段的統計能量分析結果與試驗結果的對比分析，提出採用模糊理論進行數據回歸處理來得到中間頻段的模擬結果，從而提出一種估算浮筏隔振效果的方法。
  12. Test results are analyzed in one third octave band spectrums mainly regarding vibration - sensitive instruments and emphasizing on low frequency band

    測試結果的分析主要是針對振動敏感儀器的，在頻域內採用1 / 3倍頻程頻譜，重點考慮低頻段的地面響應。
  13. The development of filters, resonators and other telecommunication technology required better dielectric materials. the dielectric materials, used as the resonate body, should be high in dielectric constant, low in dielectric loss and a near zero temperature coefficient of dielectric constant in high frequency band, also could be sintered in a relative low temperature so as to reduce production cost, and what ’ s more, the miniaturization and reliability of materials are also the main aspects in the research work of high frequency band dielectric materials

    隨著濾波器、諧振器等器件以及通信技術的發展，人們對電介質材料的要求越來越高，要求作為介質諧振腔的電介質材料在高頻段下具有高介電常數，低介電損耗，接近於零的介電常數溫度系數，還要求高頻電介質材料能夠在較低的燒結溫度下燒成，以降低實際生產的成本，此外，材料的小型化，高可靠性也是高技術高頻介質材料的重要研究方向。
  14. The essential requirements for the frequency synthesizer are : 1 ). low side band power 2 ). high hopping speed 3 ). short convergence time direct digital synthesis technology has the advantages of low cost, low power consumption, high frequency discrimination and short switching time

    直接數字合成技術dds具有低成本、低功耗、高解析度和快速轉換時間等優點，是實現快速跳頻的一個關鍵技術。本文討論了如何實現高速的跳頻系統。
  15. The design of low frequency narrow band - pass quartz crystal filter

    低頻窄帶石英晶體濾波器的研製
  16. 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。
  17. As for frequency domain, tirls includes mainly 3 frequency bands : ( 1 ) high frequency band with period less than 1 year, which is relative to weather ; ( 2 ) mid frequency band with predominant period 1 year, relative to sun, plant and season ; ( 3 ) low frequency band with period more than 1 year, relative to the crustal activity and long period variation of atmosphere temperature

    從頻率域看，地表熱紅外輻射主要存在3種頻段： （ l ）高頻，周期小於1年的天氣變化； （ 2 ）中頻，以1年周期為主的太陽、植被與季節變化； （ 3 ）低頻，大於1年周期的大氣變化的長周期成份，地殼緩慢的運動引起的熱輻射變化亦屬于長周期變化。
  18. And waveguide has a too large structure to satisfy the requirement when working at a low frequency band

    而波導天線傳感器在衰減較小的低頻區尺寸太大也達不到要求。
  19. Vibration of automobile in low frequency band has importment effect on automobile performance and the air spring has high performance in this frequency band, the semi - suspension with controllable spring stiffeness can be used widely to improve the vehicle ' s ride comfort

    由於車輛行駛的平順性關注的是低頻振動，而空氣彈簧本身在低頻處具有良好的減振性能，所以利用空氣彈簧組成的變剛度半主動懸架系統具有很好的應用前景。
  20. This system realizes the underwater distance mobile security communication. the only shortage is the low velocity, which is result from the speciality of underwater channel and that spread spectrum need big frequency band

    採用這一技術的水聲通信實驗系統成功的進行了湖上試驗，這種技術的不足是通信速率較低，這是由於水聲通道的特殊性以及擴頻技術要佔用大量帶寬所致。
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