頻帶擴展比 的英文怎麼說
中文拼音 [bīndàikuòzhǎnbǐ]
頻帶擴展比
英文
bandwidth expansion ratio-
For bowtie antennas, this method can produce a better return loss in the higher frequency band than the original ones, and at the same time, the radiation pattern bandwidths of the new antennas can be broadened more or less
對蝴蝶結天線而言，應用這種方法得到的蝴蝶結天線在高頻段比原天線具有更好的反射損耗，天線的方向圖帶寬有不同程度的擴展。By theory and practice simulation, the several types of constant envelope modulation techniques are analyzed and compared, including theirs modulation principle, phase path, the modulated wave envelope, power spectrums, error bit rate and the influence of its power spectrums of the band - limited and non - linear, etc. especially we have researched the ijf - oqpsk modulation technique, and the performance of its inter - symbol interference and time jitter free, and its strongly resisting of spectral spreading
結合理論和實驗模擬結果，分析討論了衛星通信中的各種恆包絡調制技術，對它們的調制原理，相位路徑，已調波包絡，功率譜密度，誤碼性能，以及帶限非線性通道對其功率譜的影響等方面都作了研究和比較。特別研究了ijf ? oqpsk在消除碼間干擾和定時抖動方面的性能及其優良的旁瓣特性和抑制頻譜擴展特性。Firstly a microstrip - fed microstrip patch antenna has been emulated and validated. on the base of this, the multi - band property of sierpinski equilateral triangle and squareness microstrip fractal patch antennas are carefully studied, and the effect of antenna ' s property by the permittivity, the size of patch, the order of the fractal and the decrease of fractal patches is depicted ; secondly on the base of analysis and comparison of performance of microstrip - fed semicircle and rectangle double - band microstrip patch antennas, warranty of dimension curtailment is offered ; finally expansion of band of those antennas above is discussed
在此基礎上，著重分析了微帶線耦合饋電的sierpinski等邊三角形微帶分形貼片天線以及sierpinski方形微帶分形貼片天線的多頻特性，給出了介質參數、貼片尺寸、分形的階數以及減少分形貼片數對微帶線耦合饋電的sierpinki等邊三角和sierpinski方形微帶分形貼片天線特性的影響；其次基於微帶線耦合饋電的半圓雙頻微帶貼片天線和矩形雙頻微帶貼片天線的性能分析和比較，提供了尺寸縮減的依據；最後對以上天線的頻帶擴展進行了探論。For the operating frequencies of modern radars and guidance 、 electronic countermeasure system 、 communication system 、 remote sense and remote measurement system expand to millimeter band step by step, the operating frequencies of t / r module raise ceaselessly. simultaneity millimeter wave t / r module which has the advantages of small dimension, lightweight, wide band is more suitable to the requirement of modern army and communication system. this paper is mainly referred to the research of t / r module in ka band
現代雷達與制導、電子對抗、通信、遙感遙測系統的工作頻率已逐步由微波波段擴展到毫米波波段，因此t / r組件的工作頻率也在不斷的上升，同時，毫米波t / r組件與微波t / r組件相比具有尺寸小、重量輕、頻帶寬等優點，更適合現代軍事和通信系統的要求。Thirdly, a modified extended chirp scaling ( ecs ) algorithm is presented, which solves the problem of producding fine focused images in the class of chirp scaling ( cs ) algorithm. lt can be used for uwb - sar imaging effectively. the phas e error produced by cs operation are analyzed. a windowed process in two dimension frequency domain before cs operation are proposed. it can improve the quality of image and widen the effectively swath and increase the peak to sidelobe ratio ( pslr )
然後針對chirpscaling （ cs ）類演算法不能對參考點精確聚焦的問題，提出了一種改進的擴展cs （ ecs ）演算法，實現了對uwb - sar的高效成像；分析了cs操作產生的相位誤差，提出在cs操作之前在二維頻率域對信號加窗，除有效提高信號的峰值旁瓣比（ pslr ）外，還可以提高圖像質量，增加有效測繪帶寬度。The main content of this paper : firstly, the basic theory and characteristics of various frequency synthetic technologies and the mixed frequency synthetic technology of dds + pll have been introduced, and the method to expand frequency bandwide has been analyzed and compared
本文的主要內容:首先介紹了各種頻率合成技術的基本原理和特點，以及dds + pll的混合頻率合成技術，並對擴展頻帶的方法進行了分析和比較。However, to achieve this objective, various technical challenges must be overcome. for example, the deployment of broad - band wireless access systems would require a transmission technique which can mitigate the detrimental effects of frequency selective fading
為達到這一目的，有一些技術問題必須得到良好的解決，比方說在寬帶通信模式下由於延遲擴展造成的頻率選擇性擴展和由多普勒效應產生的通道時域衰落。分享友人