發(fā)布時(shí)間：2018-03-30 04:39

  本文選題：短波通信　切入點(diǎn)：抗干擾波形　出處：《西安電子科技大學(xué)》2014年碩士論文

【摘要】：短波抗干擾數(shù)傳指的是在很強(qiáng)的信號(hào)干擾,低信噪比下,在常規(guī)通信系統(tǒng)無(wú)法實(shí)現(xiàn)正常信息傳輸情況下,以極低的信息量傳輸來(lái)保證通信鏈路正常的一種數(shù)據(jù)通信方式。短波抗干擾數(shù)傳能有效克服極低信噪比,較強(qiáng)的窄帶干擾和較大的多徑,在軍事通信和民用領(lǐng)域中有重要意義。本文所討論的題目是基于對(duì)第三代短波通信系統(tǒng)物理層的波形性能提升改造這個(gè)背景。在比較惡劣的通信環(huán)境下,盡可能實(shí)時(shí)準(zhǔn)確地傳輸數(shù)據(jù)是人們對(duì)短波通信的需求。對(duì)短波抗干擾傳輸系統(tǒng)進(jìn)行了研究,主要研究?jī)?nèi)容有以下幾條:1、結(jié)合工程實(shí)踐,本文中所設(shè)計(jì)的抗干擾數(shù)傳采用直序擴(kuò)頻方式,期望實(shí)現(xiàn)信噪比-20dB,多徑大于十幾毫秒的惡劣條件下的低速率信息傳輸,以確保在以75~2400bps等常規(guī)數(shù)據(jù)傳輸技術(shù)失效的情況下,實(shí)現(xiàn)少量有效的正常通信。2、短波抗干擾數(shù)傳中,信號(hào)捕獲問(wèn)題是數(shù)據(jù)接收過(guò)程中的關(guān)鍵技術(shù)問(wèn)題,其抗干擾性能對(duì)整個(gè)系統(tǒng)性能有直接影響,在設(shè)計(jì)時(shí)必須充分考慮到極低信噪比下,短時(shí)突發(fā)信號(hào)的檢測(cè)概率及虛警率對(duì)系統(tǒng)性能的影響。為此結(jié)合工程實(shí)際,提出了一種基于短PN分組的頻域信號(hào)捕獲算法,并詳細(xì)的分析了該算法的性能。3、本文提出一種非線(xiàn)性多環(huán)路窄帶干擾抑制算法,該算法為降低抑制干擾所引起的偽碼信號(hào)失真,通過(guò)非線(xiàn)性判決反饋電路,判決反饋系統(tǒng)利用估算的偽碼或擴(kuò)頻碼CHIP序列來(lái)得出干擾信號(hào)的估算值,減少抑制噪聲。然后將該估算值作為參照輸入送入自適應(yīng)濾波器。由于參照信號(hào)與原始信號(hào)的擴(kuò)頻碼相關(guān)減小,此判決反饋能更好地抑制干擾且減少擴(kuò)頻信號(hào)的失真,有效提高了抗干擾能力。4、在抗干擾波形的關(guān)鍵技術(shù)軟件仿真完成后,設(shè)計(jì)出適用于以TMS320C5509為核心的抗干擾波形的短波數(shù)字處理平臺(tái),完成了硬件的上變頻設(shè)計(jì)、下變頻設(shè)計(jì)及自動(dòng)增益設(shè)計(jì)等,然后給出具體軟件實(shí)現(xiàn)的流程。并在信道模擬器上進(jìn)行了指標(biāo)測(cè)試,實(shí)測(cè)結(jié)果驗(yàn)證了該設(shè)計(jì)方法的可行性和有效性。
[Abstract]:Shortwave anti-jamming data transmission means that under the condition of strong signal interference and low signal-to-noise ratio (SNR), the normal information transmission can not be realized in the conventional communication system. A data communication mode with very low amount of information to ensure the normal communication link. Shortwave anti-jamming data transmission can effectively overcome extremely low signal-to-noise ratio (SNR), strong narrowband interference and large multipath. This paper is based on the background of improving the waveform performance of the physical layer of the third generation shortwave communication system. The transmission of data in real time and accurate is the demand of people for shortwave communication. In this paper, the research on shortwave anti-jamming transmission system is carried out. The main research contents are as follows: 1, combined with engineering practice, In this paper, the design of anti-jamming data transmission adopts direct sequence spread spectrum mode, in order to realize the low rate information transmission under the bad condition of signal-to-noise ratio (SNR) -20dB and multipath more than 10 milliseconds, so as to ensure the failure of conventional data transmission technology such as 75~2400bps. In short wave anti-jamming data transmission, signal acquisition is a key technical problem in the process of data receiving, and its anti-jamming performance has a direct impact on the performance of the whole system. The influence of detection probability and false alarm rate of short time burst signal on system performance must be fully taken into account in the design. A frequency domain signal acquisition algorithm based on short PN packet is proposed. The performance of the algorithm is analyzed in detail. A nonlinear multi-loop narrowband interference suppression algorithm is proposed in this paper. In order to reduce the pseudo code signal distortion caused by interference suppression, the nonlinear decision feedback circuit is used. The decision feedback system uses the estimated pseudo code or spread spectrum code CHIP sequence to obtain the estimated value of the interference signal. The estimation is then fed into the adaptive filter as a reference input. Since the correlation between the reference signal and the original signal is reduced, the decision feedback can better suppress the interference and reduce the distortion of the spread spectrum signal. After the simulation of the key technology and software of the anti-jamming waveform is completed, a short-wave digital processing platform suitable for anti-jamming waveform with TMS320C5509 as the core is designed, and the up-conversion design of the hardware is completed. The downconversion design and the automatic gain design are given, and the flow chart of the software implementation is given. The test results on the channel simulator show that the design method is feasible and effective.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TN973

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本文編號(hào)：1684431