frequency code signal 中文意思是什麼
frequency code signal
解釋
頻率碼信號-
In the fourth chapter, firstly, the fsk / psk signal function is presented, then, the signal which frequency and phase are modulated by costas code and barker code for each are analyzed at the same time. after that, the target returns and clutter returns are analyzed and modeled. at last, both of the time correlation characteristics and space correlation characteristics are theoretically analyzed
在第四章中，首先給出fsk / psk信號的表達式，並對一種分別採用costas碼和barker碼進行頻率和相位調制的fsk / psk信號進行分析，然後對fsk / psk信號的目標回波和雜亂回波進行分析與建模，接著，對雜波信號的時間相關性和空間相關性進行理論分析，由分析結果可知， fsk / psk雷達雜波的時間相關性不變、空間相關性增強。 -
Digital speech has preponderance over analog speech in reliability, robustness and security during communication. however, digital speech needs more bandwidth than the analog signal. especially with the requirement for communication frequency increasing, it ' s necessary to code speech signal at low rates
但是，數字化后的信號所佔的頻帶大幅增加，特別是在帶寬需求日益增長的今天，這個問題尤為突出，因此語音的低速率編碼（即壓縮編碼）成為迫切的要求。 -
Secondly, the dissertation presents a 3 - dimensional searching method with afc and pn code synchronization and adaptive array convergence in order to accurately estimate the frequency difference between the received signal and the local oscillator
其次，為了準確估計接收信號和本地振蕩器之間的頻差，提出了afc 、 pn碼同步、自適應陣收斂的三維搜索策略。 -
In order to meet to the higher timing precision of the low frequency time - code timing terminal, the applications of dsp ( digital signal processing technology ) in the time service is researched in this paper. the main works and contributions can be summarized as follows : ( l ) the low frequency signal transmission and dsp technology are discussed. according to the system needs, a testing flat of low frequency time - code based on dsp is built up
本論文的工作針對低頻時碼授時高端用戶的定時需求，對數字信號處理（ dsp ）這一新型技術在該領域應用進行了探索性研究，主要完成和開展了如下工作： （ 1 ）研究分析了低頻通道和dsp技術，根據系統要求，從硬體上實現了基於dsp晶元的低頻時碼信號的採集測試平臺。 -
In this thesis, the signal express format and characteristic of pulse internal phase modulation and pulse external frequency agile is introduced, and the signal design is processed based on the demand of radar system, the restriction of parameter design and various code format
本文首先介紹了脈內調相脈間跳頻信號的表達形式和特點，並根據雷達系統的需求和參數設計的約束條件以及不同的編碼形式進行了信號的設計。 -
Frequency code is not uniformity distribution and keeps to a probability distribution function defined by the spectral characteristics of the target of interest. the phase code is equally duality pseudo - random sequence and used to reduced the sidelobes of the signal correlation function. and the mismatch - phase sequence is corresponding with the frequency sequence one by one
而頻率編碼為不均勻分佈，由所觀測目標的頻譜信息提取出概率密度函數決定頻率編碼序列的分佈；相位編碼為二元的偽隨機序列，採取均勻的二相編碼，消減同頻脈沖帶來的過高的相關函數的旁瓣；而失配相位為與頻率編碼相一一對應于各子脈沖中。 -
Ds signal is twice modulated with the rapid pseudorandom noise sequence and the carrier. so it appears cyclostationary. in the field of spectral correlation, ds signals appears its characteristic as fallows : for the amplitude of spectral correlation, the information of carrier frequency and pn code rate are contained on the spectrum frequency equal to zero sheet, and also the pn code rate is contained on the sheet of spectrum frequency equal to carrier frequency ; for the phase of spectral correlation, the information of carrier initial phase is contained on the sheet of cyclic frequency equal to double carrier frequency
Ds信號是經過高速偽隨機序列和正弦載波二次調制的寬帶信號，因此具有周期平穩特性，它在譜相關域表現為:幅頻特性在譜頻率等於零截面切片上包含了載頻和偽碼速率信息特徵，在譜頻率等於載頻截面切片上包含了偽碼速率信息特徵;相頻特性在循環頻率等於兩倍載頻截面切片上包含了載波初相信息特徵。 -
At the last we program the parameter detecting methods for frequency - shift track signal with c language and assembly language base on code composer studio of dsp. then we realize it on the dsp chip of tms320f2812. experiments shows that it can satisfy the demand of real time and precision
最後在dsp的集成開發環境ccs （ codecomposerstudio ）上採用c語言和匯編語言混合編寫移頻軌道信號的參數檢測演算法，並將該演算法移植到dsp晶元（ tms320f2812 ）上實現，測試結果表明上述演算法能夠滿足實時性和精度的要求。 -
However, multipath components can be resolvable due to the autocorrelation of the spread spectrum signal, thus the optimal receiver equals coherent rake reception, i. e. maximum ratio combining the independent components which endure flat fading or frequency non - selective fading. synchronization of pn code and separation of resolvable multipath components need to estimate the exact time delay among the multipath components
但是利用擴頻信號的自相關特性，可分辨多徑可以被有效分離，最優接收機等效為對多個具有獨立平坦衰落通道（或頻率非選擇性通道）特性的多徑信號進行最大比合併，即相干rake接收。 -
In pulse code modulation, a spurious signal formed from beats between the signal frequency and the sample frequency
在脈沖編碼調制中，信號頻率和取樣頻率之間的差拍所引起的偽信號。 -
In this thesis, a kind of 2 - dimention signal acquisition method is presented which combines parallel pn code phase and carrier frequency acquisition, as a result the acquisition time is shortened greatly. besides, according to the fact that the detection of spread spectrum signals is always the key point in the receiving system
在擴頻信號的捕獲過程中要求有較小的時延和較高的概率，本文介紹一種二維信號的捕獲方法，這種方法結合偽pn碼和載波頻率的獲取，捕獲時延將大幅度降低，實際上，擴頻信號的檢測是接收系統的關鍵。 -
First, the thesis introduced conception and characters of software radio ; second, the thesis analyzed architectures of software radio ; third, the thesis discussed critical technologies of software radio and applications of dsp in software radio, moreover, realized arithmetic of crc coding, convolution code, orthogonal digital frequency conversion and multi - speeds signal process ; finally, the thesis prospected foreground of software radio
本文首先介紹了軟體無線電的概念和特徵，接著分析了軟體無線電體系結構，論述了軟體無線電的關鍵技術及dsp在軟體無線電中的應用，在tms320c54x上實現了crc編碼、卷積碼，完成了正交數字變頻和多速率信號處理的dsp演算法，最後展望了軟體無線電的應用前景。 -
In the end, implementation of if digital receiver unit of tdrss user transponder by the method of fpga and dsp cooperation design are completed successfully, which leads to good ds - ss if receiver design for the signal whose carrier frequency is 3mhz, pseudorandom code rate is 3mchips / s, data rate is 10kbps, frequency offset is no more 1khz, and modulation mode is bpsk
最後，完成了該中頻數字接收機設計，並對其進行調試和測試。測試結果表明，該接收機能對載頻為3mhz ，頻偏不大於1khz ，偽隨機碼速率為3mchips / s ，信息碼速率為10kbps ， bpsk調制的直接序列擴頻中頻信號進行接收，基本滿足設計要求。 -
The problem of signal processing for direct - sequence code - division - multiple - access ( ds - cdma ) signal over multipath frequency - selective mobile channels is considered. a new blind receiver is proposed. without the knowledge of the multiple - access interference users spreading code and the channel characteristics, the receiver achieves blind detection with prior knowledge of only the desired users spreading code and approximate timing. by using reduced rank adaptive decorrelating filter and adaptive multipath combiner which is based on decision - directed algorithm, the receiver gets the ability to combat both fading and the near - far effect at low cost. simulation results demonstrate that the proposed receiver offers high performance
本文研究多徑頻率選擇性衰落通道下直接序列擴頻碼分多址（ ds - cdma ）信號的處理問題，提出了一種新型的盲接收機.該接收機不需預知多址干擾用戶的擴頻碼，不需預知通道參數，只需已知期望用戶的擴頻碼和粗略的定時，就可以完成用戶的盲檢測.同時，該接收機通過降維自適應去相關濾波和基於判決指導的自適應多徑合併，來獲得低成本和良好的抗衰落、抗遠近效應性能.模擬結果驗證了本文提出的接收機的優良性能
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