短噪聲脈沖 的英文怎麼說
中文拼音 [duǎnzàoshēngmàichōng]
短噪聲脈沖
英文
short noise burst-
On the design of the system, the thickness measure system of mems chip is built based on lbu and pump - probe technology. on the analysis of data, the reflectivity curve is analyzed using the law of reflectivity change induced by ultrasound, and the thickness is calculated using the system designed by the article, to aluminum film the size of about 20nm can be measured, when the film be measured is single layer, the relative error of the system is less than 2 %, when the film be measured is double layer, the relative error of the system is less than 10 %
在基礎理論方面研究了激光（特別是超短脈沖激光）超聲的激勵機理，探討了激光調制技術以提高系統信噪比，闡述了泵束探針束技術及相關實驗設置；在系統設計上，以激光超聲為基本原理，以泵束探針束技術為系統設計方案完成了mems基片厚度測量系統的設計；在數據分析方法上，利用聲致光反射率變化的一般規律對測得的光反射率曲線進行分析，確定超聲回波在薄膜兩界面間來回傳播的時間，以計算薄膜的厚度。This paper gives a time - synchronization technique bases on gps time service signal which is used in broad band seismic recorder 。 by world coordination time offered by gps - - utc ( usno ), adjust local clock base on gps signal, gain high nicety clock signal, clock precision reachs 10 - 6 。 this clock is the time source of broad band seismic recorder, bring the whole seismic recorder works in same time base. 1pps time base with high stability can be used as in - phase, spring, time and start - stop of every collection mode, while the scale under second make a precise time mark to receive data of broad band seismic recorder
針對接收機中gps信號的噪聲進行kalman濾波軟體處理， kalman濾波可以對gps信號與本地晶振時鐘的時差數據在大噪聲中進行平滑，在較短時間內估計出高精度的時差數據。系統消除了gps秒脈沖信號的ms級隨機誤差，把晶振秒脈沖的長期穩定度鎖定到gps信號的穩定度上;在gps信號失效時給出了可行措施，能夠保證在任何情況下產生一個穩定、高精度秒脈沖信號，誤差在1 s內。Simulator presented in this paper provides a direct interface for the test of shortwave communication system, which well represents various features of hf channel such as multi - path delay, rayleigh fading, doppler shift, doppler spread, gaussian noise and impulsive interference, etc. in order to realize the channel simulation for the intermediate frequency signal, we, inspired by the idea of soft - defined radio, bring forward a new design method that the channel simulator consists of several dsp chips
本文研製的模擬器提供介面直接對短波通信系統進行測試，能夠全面反映短波通道的多徑時延、瑞利衰落、多普勒頻移、多普勒擴展、高斯噪聲和脈沖干擾等特性。為了實現對中頻信號的通道模擬，開發出一個結合軟體無線電思想的由多個數字信號處理晶元構成的短波通道物理模擬器。
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