C波段寬帶正交調(diào)制載波泄漏高抑制技術(shù)的實(shí)現(xiàn)
發(fā)布時(shí)間：2018-09-03 08:30
【摘要】：I/Q正交調(diào)制是通信系統(tǒng)中的主要調(diào)制方式之一。單芯片I/Q正交調(diào)制器是目前通信系統(tǒng)主要的硬件實(shí)現(xiàn)平臺。但受工藝以及器件誤差的影響,在寬頻帶正交調(diào)制系統(tǒng)中,單芯片調(diào)制器的I/Q直流偏置很難實(shí)現(xiàn)一致,從而導(dǎo)致調(diào)制輸出端存在載波泄漏。在正交調(diào)制設(shè)備中,載波泄漏過大,將會增加系統(tǒng)后級PA的非線性,使得發(fā)射EVM性能下降,同時(shí)還會降低系統(tǒng)接收端的靈敏度,使誤碼率增高,從而直接降低系統(tǒng)的性能。本文所研制的設(shè)備主要應(yīng)用于C波段寬帶衛(wèi)星通信系統(tǒng)中心站,頻率覆蓋范圍2.4GHz~4GHz,系統(tǒng)要求正交調(diào)制設(shè)備的載波泄漏抑制為50dB,本文所研究的技術(shù)正是基于實(shí)現(xiàn)該指標(biāo)而開展的。在寬頻帶正交調(diào)制系統(tǒng)中,產(chǎn)生載波泄漏的主要原因是由于輸入到調(diào)制器的I/Q支路直流偏置的不平衡導(dǎo)致。因此要實(shí)現(xiàn)正交調(diào)制載波泄漏抑制,需要對調(diào)制器I/Q兩路信號的直流偏置進(jìn)行修正。目前修正正交調(diào)制I/Q直流偏置的方法主要有平衡技術(shù)、載波相移技術(shù)、基于功率檢測器的矯正技術(shù)、數(shù)字基帶矯正技術(shù)等。平衡技術(shù)主要用于窄帶系統(tǒng);載波相移技術(shù)、基于功率檢測校準(zhǔn)技術(shù)以及數(shù)字基帶矯正技術(shù)雖然可實(shí)現(xiàn)較好的載波泄漏的抑制,但是需要增加復(fù)雜的硬件路,從而增加設(shè)備體積、成本以及功耗�；谏鲜龈鞣桨傅奶攸c(diǎn),本文提出了一種基于LXI頻譜儀LAN口自動(dòng)閉環(huán)修正正交調(diào)制I/Q直流偏置修正技術(shù)。該技術(shù)主要是利用LXI儀器廠家提供的LXI接口規(guī)范,在PC機(jī)安裝LXI儀器廠家提供的動(dòng)態(tài)庫驅(qū)動(dòng)文件,然后編程通過LAN口讀取LXI儀器動(dòng)態(tài)庫文件中功率和頻率測試參數(shù),再通過配置正交調(diào)制設(shè)備中DA寄存器參數(shù)對其I/Q直流偏置進(jìn)行修正。該技術(shù)的特點(diǎn)是采用自動(dòng)閉環(huán)的方式,在不增加檢波、AD、變頻等硬件電路的情況下,實(shí)現(xiàn)對正交調(diào)制載波泄漏的高抑制,極大降低了設(shè)備的體積和成本。在-40℃~+70℃全溫范圍,本文實(shí)現(xiàn)了2.4GHz~4GHz頻率范圍載波泄漏60dB抑制,最終完成了8套設(shè)備的研制。本文研究的技術(shù)理論上可實(shí)用于任何頻帶的正交調(diào)制系統(tǒng),是一種非常有意義的技術(shù)。
[Abstract]:I / Q quadrature modulation is one of the main modulation methods in communication systems. Single chip I / Q quadrature modulator is the main hardware implementation platform of current communication system. However, due to the influence of process and device errors, I / Q DC bias of single chip modulator is difficult to achieve in broadband quadrature modulation system, which leads to carrier leakage in modulation output. In quadrature modulation equipment, if the carrier leakage is too large, it will increase the nonlinearity of the post-stage PA of the system and make the transmitting EVM performance decline. At the same time, it will also reduce the sensitivity of the system receiver and increase the bit error rate, thus directly reducing the performance of the system. The equipment developed in this paper is mainly used in the central station of C-band broadband satellite communication system with a frequency coverage range of 2.4 GHz and 4 GHz, and the carrier leakage suppression of the quadrature modulation equipment is required to be 50 dB. The technology studied in this paper is based on the realization of this index. In a broadband quadrature modulation system, the main cause of carrier leakage is the imbalance of the I / Q branch DC bias input to the modulator. Therefore, in order to suppress the leakage of orthogonal modulation carrier, the DC bias of the modulator I / Q signal needs to be corrected. At present, the methods of correcting I / Q DC bias by orthogonal modulation mainly include balance technique, carrier phase shift technique, power detector based correction technology, digital baseband correction technology and so on. Balance technology is mainly used in narrow band system, carrier phase shift technology, based on power detection and calibration technology and digital baseband correction technology can achieve better carrier leakage suppression, but need to add complex hardware circuit. This increases the volume, cost, and power consumption of the device. Based on the characteristics of the above schemes, an I / Q DC bias correction technique based on LAN port automatic closed-loop correction for LXI spectrometer is presented in this paper. This technology mainly uses the LXI interface specification provided by the LXI instrument manufacturer to install the dynamic library driver file provided by the LXI instrument manufacturer on the PC machine, and then program to read the power and frequency test parameters of the LXI instrument dynamic library file through the LAN port. Then the I / Q DC bias is corrected by configuring the parameters of the DA register in the quadrature modulation equipment. The characteristic of this technique is that it can reduce the leakage of quadrature modulation carrier and greatly reduce the volume and cost of the equipment without adding the hardware circuits such as ADD frequency conversion and so on. In the full temperature range of -40 鈩，
本文編號：2219440
[Abstract]:I / Q quadrature modulation is one of the main modulation methods in communication systems. Single chip I / Q quadrature modulator is the main hardware implementation platform of current communication system. However, due to the influence of process and device errors, I / Q DC bias of single chip modulator is difficult to achieve in broadband quadrature modulation system, which leads to carrier leakage in modulation output. In quadrature modulation equipment, if the carrier leakage is too large, it will increase the nonlinearity of the post-stage PA of the system and make the transmitting EVM performance decline. At the same time, it will also reduce the sensitivity of the system receiver and increase the bit error rate, thus directly reducing the performance of the system. The equipment developed in this paper is mainly used in the central station of C-band broadband satellite communication system with a frequency coverage range of 2.4 GHz and 4 GHz, and the carrier leakage suppression of the quadrature modulation equipment is required to be 50 dB. The technology studied in this paper is based on the realization of this index. In a broadband quadrature modulation system, the main cause of carrier leakage is the imbalance of the I / Q branch DC bias input to the modulator. Therefore, in order to suppress the leakage of orthogonal modulation carrier, the DC bias of the modulator I / Q signal needs to be corrected. At present, the methods of correcting I / Q DC bias by orthogonal modulation mainly include balance technique, carrier phase shift technique, power detector based correction technology, digital baseband correction technology and so on. Balance technology is mainly used in narrow band system, carrier phase shift technology, based on power detection and calibration technology and digital baseband correction technology can achieve better carrier leakage suppression, but need to add complex hardware circuit. This increases the volume, cost, and power consumption of the device. Based on the characteristics of the above schemes, an I / Q DC bias correction technique based on LAN port automatic closed-loop correction for LXI spectrometer is presented in this paper. This technology mainly uses the LXI interface specification provided by the LXI instrument manufacturer to install the dynamic library driver file provided by the LXI instrument manufacturer on the PC machine, and then program to read the power and frequency test parameters of the LXI instrument dynamic library file through the LAN port. Then the I / Q DC bias is corrected by configuring the parameters of the DA register in the quadrature modulation equipment. The characteristic of this technique is that it can reduce the leakage of quadrature modulation carrier and greatly reduce the volume and cost of the equipment without adding the hardware circuits such as ADD frequency conversion and so on. In the full temperature range of -40 鈩，
本文編號：2219440
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