窄帶頻率 的英文怎麼說
中文拼音 [zhǎidàibīnlǜ]
窄帶頻率
英文
narrow band frequency-
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。Telegraphy using frequency modulationnarrow band direct printing
頻率調制發射窄帶印字系統In the past few years, there has been significant interest in digital video applications like video conferencing and video e - mailing over internet, video telephony over public switched telephone networks ( pstn ) and wireless networks, etc. by removing spatio - temporal redundancies existing in adjacent frames, motion estimation can reduce the coding bit - rate significantly
低速率視頻編碼技術已在許多領域得到了應用,如在pstn (公共電話網) 、無線網、 n - isdn (窄帶綜合業務數字網) 、 b - isdn (寬帶綜合業務數字網)上傳輸視頻會議、可視電話和無線手持終端等。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。A novel joint estimation algorithm for ranges, frequencies and doas of multiple near - field narrowband sources is proposed in the near field is proposed
摘要提出了一種新的多個近場窄帶信源距離、頻率及到達角三維參數的聯合估計演算法。Pll has the excellent narrow - band - tracking - filtering characteristic. in this scheme, we combine the merits of dds and pll
該方案是將dds的高解析度、高精確度、頻率變化易於控制的優點與pll良好的窄帶跟蹤性能相結合。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。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。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。Female courtship signal of the brown planthopper was made of many continuous regular pulses and male ' s signal was made of similar syllabics and had two types with different time domain characteristics. second male vibrational signal differed from male courtship signal with wide spectrum range and regular syllabics frequency. time domain characteristics of signals in different individuals even the same individual were different
頻域特徵分析知,褐飛虱雌蟲求偶嗚聲信號的頻域特性較穩定,個體內比個體間差異小;雄蟲求偶嗚聲信號s 、 e片段頻譜范圍較寬,但主振頻率比較接近,差異不顯著; m片段頻帶較窄,主振頻率mvf略小於s 、 e片段,變異較小; m片段脈沖重復頻率prf為幻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。Lastly, the paper designs an example and tests its amplitude frequency response. at last, this paper points out that this method can efficiently control the performance of narrow band fir digital filters. both test and application indicate that practical performance and ideal performance are almost identical
在此基礎上給出窄帶fir濾波器的詳細結構,分析了窄帶fir濾波器的多級實現原理,並且對窄帶fir濾波器的的基本特性進行了分析,這些特性包括:頻率特性、抗混疊特性、去鏡象特性。This master ’ s degree thesis firstly introduces and discusses the principle of ofdm and the merged blue print for digital terrestrial television broadcasting in china, then proposes a scheme for the test platform of narrowband ldpc decoding efficiency based on fpga. this scheme includes techniques such as time - domain synchronization using pn and power estimation using pilots
本論文首先介紹並討論了數字電視傳輸標準tds - ofdm的實現原理,對其中的一些關鍵問題做了詳細的分析,在此基礎上提出了一種基於fpga的窄帶ldpc解碼-誤碼測試平臺設計方案,即利用時域pn頭同步及頻域導頻進行功率估計的fpga設計。Very low bit rate video coding is a hotspot in video processing field in these years. it supplies a gap of application in narrowband channel
甚低碼率視頻圖像編碼技術是近年來視頻處理領域的一個研究熱點,它的出現填補了視頻通信在窄帶通道上應用的空白。In this paper, the theory and implementing method of video encoder based on the itu - t h. 263 video coding for low bit rate communication standard are studied deeply in order to satisfy the demand of narrow - band video communication
為了在窄帶通道上實現視頻通信,本文對基於itu - t的低比特率視頻通信編碼標準h 263的視頻編碼器的原理和實現方法作了深入的研究。The echolocating calls in the state of fly were compared with those in the state of hang in two kinds of bats, r. yunanensis and h. pratti, and the doppler compensation effect was described. the analyzing result indicated that the frequency in hang was higher that that in fly, the duration and interpulse duration in hang were longer than those in fly, and the fm bandwidth in hang was narrower than that in fly
比較了雲南菊頭蝠和普氏蹄蝠飛行狀態和懸掛狀態下的回聲定位聲波,描述這2種蝙蝠的多普勒補償效應,懸掛狀態聲波頻率顯著高於飛行狀態,聲脈沖時間和間隔時間顯著長于飛行狀態, fm帶寬窄于飛行狀態。Secondly, ground on the duct noise control, the delayed - lms algorithm, which is actulized easily, is brought forward, then the simulation on pc is achieved. it is shown from the computer simulation that for the single frequency noise, there will be a good effect when choosing the suitable parameters ; but for the narrowband noise, the effect will become worse with increasement of the bandwidth. this result is helpful to analyze the parameters influencing anc
結果表明: ( 1 )隨著濾波器長度的增大,系統收斂速度變快; ( 2 )隨著值的增大,系統的收斂速度增大,但是當值超過某一范圍時會引起系統的發散; ( 3 )次級通路的延遲數與初級噪聲頻率有關; ( 4 )對于窄帶信號, dlms演算法可以取得一定的降噪量,但是隨著窄帶信號帶寬的增大,降噪效果明顯變差。With the rapid development of software radio techniques, the sampling rate is becoming high. on the condition of high sampling rate, the design of narrow band fir digital filters by usual ways is impossible
隨著軟體無線電技術的發展,使信號的采樣頻率越來越高,而在高采樣率的條件下,採用常規的方法進行窄帶fir濾波器的設計是不可能的。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。The accurately controlled signal source generates sinusoidal elastic wave accurately controlled in frequency and stable in phase to " illustrate " underground media. time signal stacker receive signal by stacking and doing fft to measure the transfer function of media. " sompi " cepstrum method retrieve group velocity travel times and decayed factors of wave element from observational data of transfer function in a limited frequency window
精密可控震源用於產生頻率精確相位穩定的正弦彈性波以照射地層內部,信號疊加器通過對接收信號進行疊加和進行傅立葉變換的方式實現對介質傳遞函數的精密測量, 「存否」倒譜方法能夠根據一段窄帶頻域傳遞函數數據獲得時域上各個波成分的群速度傳播時間和介質衰減因子。分享友人