narrow frequency 中文意思是什麼

narrow frequency 解釋
窄頻帶
  • narrow : adj 1 狹 窄 狹隘的 狹小的 （opp broad wide）。2 有限的 受限制的；有偏見的 氣量小的 心眼兒窄的；眼...
  • 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。
  1. Due to existing signal processing technology ’ s shortage such aslow measurement, narrow measurement range precision and other poor performance, we introduced a high - precise signal processing technology : firstly, to get power spectrum with hanning windowed welch modified periodogram, search its peak value frequency ; secondly, to apply zooming analysis via goertzel algorithm ; at last, to get a highly precise doppler frequency with energy centrobaric rectifying algorithm 。 the simulating result indicated that this technology introduced could get accurate doppler frequency 。 depending on above discussed technology, we designed a signal processing scheme, and developed a signal processing system. the running result showed high performance, verified the feasibility and reliability of the highly precise signal processing technology introduced. in a word, the technology improved ldv ’ s performance such as measurement precision, measurement range, dynamic response time 。 and it will have a wide application foreground

    針對存在的缺點，本文提出了一種應用於激光多普勒測速的高精度信號處理技術，即首先利用加hanning窗的welch修正周期圖演算法得到信號功率譜，搜索其譜峰值頻率，接著利用goertzel頻譜細化演算法對搜索的譜峰進行細化分析，再引入能量重心頻譜校正演算法對細化后的譜峰進行校正分析，從而將離散頻譜分析演算法、頻譜細化演算法和頻譜校正演算法三者有機結合起來，充分發揮各自的優點:通過加hanning窗的welch修正周期圖演算法快速得到功率譜及峰值頻率，通過goertzel演算法獲得分析頻帶的高解析度頻譜，然後通過能量重心校正演算法對細化后的頻譜進行高精度校正，這樣不僅保證了演算法的高效性，而且大大提高了分析的精度。
  2. At. detail specification for cold welded seal quartz crystal units for oscillator applications - dn, dq and dp enclosures, 17 to 75 mhz frequency range - third overtone thickness - shear mode, at - cut, for operation over narrow temperature ranges temperature controlled - full assessment level

    振蕩器用冷焊密封石英晶體振子詳細規范. dn dq和dp外殼17至75mhz頻率范圍.窄溫范圍
  3. At. detail specification for cold welded seal quartz crystal units for oscillator applications - dn, dq and dp enclosures, 50 to 125 mhz frequency range - fifth overtone thickness - shear mode, at - cut, for operation over narrow temperature ranges temperature controlled - full assessment level

    經質量評定的振蕩器用冷焊封石英晶體振子詳細規范. dn dq和dp外殼， 50至125mhz頻率規范.窄溫范圍
  4. At. detail specification for cold welded seal quartz crystal units for oscillator applications - dn, dq and dp enclosures, 0. 8 to 20 mhz and 3. 0 to 30 mhz frequency ranges - fundamental thickness - shear mode, at - cut, for operation over narrow temperature ranges temperature controlled - full assessment level

    振蕩器用冷焊密封石英晶體振子詳細規范. dn dq和dp外殼0 . 8至20mhz和3 . 0到30mhz頻率范圍.窄溫范圍
  5. Many bats emit an echolocation call that contains a narrow frequency range and then analyze returning echoes to navigate and to detect prey

    許多蝙蝠會發出頻率?圍狹窄的回聲定位呼叫，然後分析回聲來作導航與偵測獵物。
  6. They are very compact in time and the frequency bands of interest are narrow.

    它們在時間上是非常緊致的同時有意義頻帶是狹的。
  7. Another attribute is the flux or radiant power that can be delivered in that narrow frequency band.

    另一個性質就是在這樣窄的頻帶內可以給出很高的光通量或輻射功率。
  8. To utilize the advantages of dsp chips, the system should be computing sources economical. according to digital signal processing theory, the poly - phase fir can help reduce the workloads of the ddc / duc. therefore, adding the complex carrier mixers, the channelization system ( a method of using a single wideband facility to transmit many relatively narrow - bandwidth signals. by subdividing the frequency spectrum used in the wideband channel ) can be formed utilizing the characters of fft

    為了使開發出的軟體可以適用於高速dsp器件開發，節省系統資源，課題首先從數字信號處理的理論進行分析，得出可以利用抽樣率轉換的數字濾波器的特點，即多相濾波實現數字上下變頻計算負擔的減小，之後進一步將多相濾波器與頻譜搬移部分結合，通過公式的推導，得出可利用快速傅立葉變換的特點實現多路信號的通道化發射和接收的處理模型。
  9. From the result we get the following conclusion : for narrow - band signal, the effect of the method based on fft is best. for wide - band signal, when snr is up to certain degree ( higher than - 7db or so ), the curves of square error of modified methods are more obvious and closer to crb. for an echo composed of more than one frequency or direction, space - frequency distribution could show more direct information of frequency and direction, which is more advantaged to make precise judge and estimation for doa of echo

    從估計結果發現，對于窄帶回波信號，基於fft的方法估計性能大大優于其他方法；對于寬帶回波信號，在信噪比達到一定程度（高於約- 7db ）時，補償后的幾種估計法的性能改善均比較明顯，誤差曲線越來越接近crb曲線；對于回波中存在多頻率多方位的情況，空間?頻率分布圖能提供較為直觀的頻率及方位信息，因此應用空間?頻率估計法來進行方位估計，更有利於進一步對回波的具體方位進行準確判斷和估計。
  10. At first some modification is made in conventional beam forming of frequency domain, namely to estimate doa by arrays outputs on compensated spacial frequency points of echoes. then the cwt is utilized to signal processing in space - frequency domain for estimation of doa, and the corresponding modification is also made. in the dissertation, the computer simulations of doa estimation for both narrow - band and wide - band echoes are given, so do the necessary comparison among several methods and crb

    首先在傳統的頻域波束形成演算法的基礎上，提出對寬帶信號的頻率補償，也即對寬帶回波信號的各空間頻率根據時間頻率的差異進行相應補償，然後對各陣元輸出求和來得到方位估計；其次將連續小波變換引入到空間?頻率處理中，從而完成對目標方位的估計，並進行了相應地補償。
  11. In optics one usually deals with a source which emits light within a narrow, but nevertheless finite, frequency range.

    在光學中，常常遇到的是這樣的光源，它所發射的光頻率范圍雖窄，但仍有一定的寬度。
  12. The merits of dds such as super fine frequency resdutlon 、 high frequency accuracy 、 easy programmed can be in combination with the excellent character of narrow - band tracing filter merits of pll

    它可以將dds的超高頻率解析度、高頻率精確度、容易實現程式控制等優點與鎖相環良好的窄帶跟蹤濾波特性相結合。
  13. 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。
  14. From some characteristics observed, such as the short lift time, narrow frequency band, fast frequency drift, quasi - periodic pulsation, spike event and complex magnetic structure, it is considered that the radiation mechanism of these events may be principally due to the electromagnetic waves magnified directly by the instable electronic cyclotron

    從它們的觀測特徵：短壽命，窄頻帶，頻率快速漂移，及尖峰事件與磁結構復雜的大黑子活動區密切相關等，認為這些事件的輻射機制可能是電子迴旋脈澤不穩定直接放大電磁波所致。
  15. 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。
  16. The controlled object hyvp ( hydraulic pressure vibration platform ) has the property of big loading pressure and rating power, so it need considerable transmitted and control power, it also has the property of high - level math model, and narrow frequency width in closed - loop, and bad stability. this thesis is based on the hpvs in the “ tiema project ”

    被控對象（液壓振動臺）具有負載壓力和額定功率相當大的特點，因此要求傳輸和控制的功率要相當可觀;而且它還具有數學模型階數高、閉環頻帶寬度窄、穩定性差等特點。
  17. There are several defects of the monitoring method using embedded optical fiber sensors, such as the narrow frequency operation band of the sensors and the expensive cost of the instrument system

    光纖傳感法也存在著不少缺點，如光纖頻帶窄、設備費用昂貴等。
  18. A large proportion of the bat ' s auditory receptors ( hair cells in the cochlea ) and large areas in the bat ' s brain are devoted to analyzing a narrow frequency range corresponding to a single harmonic of the returning echo

    蝙蝠用很大一部分的聽覺受器（耳蝸中的毛細胞）與大幅的腦部區域，來分析一段?圍狹窄的頻率，該頻率正與回聲的一個諧波相符。
  19. In this thesis, a kind of software method is researched to realize the functions of fast acquisition, tracking and demodulation of pcm - cdma - bpsk intermediate frequency signals. conventional research on spread spectrum signals is in the case of ideal conditions, such as low code rate, narrow dynamic range, narrow frequency - changing range and so on

    本論文將介紹一種軟體模擬硬體的方法來實現pcm - cdma - bpsk中頻信號的快捕、跟蹤和解調。關于擴頻信號的傳統的研究是在理想的條件下，比如低碼率、窄動態范圍、窄頻率變化范圍等等。
  20. Only photons in a very narrow frequency range can be emitted by any material. led s that emit different colors are made of different semi - conductor materials, and require different energies to light them

    以上僅為led並檔使用的推薦辦法，在實際生產中，用戶則可以根據自己產品的特點進行相應的調整或以其它的辦法使用。
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