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由于各种因素的影响,I/Q通道之间通常会发生失配现象,这会降低接收机的动态范围,进而影响接收机的性能。本文提出了一种宽带接收机中L/Q幅相误差校正的数字方法:首先通过一种时域方法以获得误差信息,籍此计算校正所需参数,再由Newton插值多项式构造滤波器组对I/Q信号进行滤波校正。仿真表明,这种数字校正方法能有效地提高宽带接收机I/Q通道的正交一致性。 相似文献
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论文首先介绍了高速调制解调器中正交调制器载波I/Q支路幅相失配的模型,然后在此模型上推导了TCM-8PSK信号误比特率性能公式,最后运用Matlab中的动态仿真工具Simulink仿真验证了推导结果。推导与仿真结果都表明,在载波I/Q幅相失配条件下TCM-8PSK信号的误比特率性能下降了。 相似文献
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针对宽带信号模拟正交下变频时产生的I/Q信号不平衡问题,本文提出了一种在数字域对I/Q信号不平衡的校正方法,建立了 I/Q信号不平衡的数字模型,分析了 I/Q信号不平衡给系统带来的影响,推导了 I/Q信号不平衡的校正方法,并对校正结果进行了仿真验证,该方法已在某设备中成功应用. 相似文献
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《无线电工程》2019,(4):298-303
在I/Q正交采样时,I/Q正交性幅相误差需要补偿。经幅相误差建模,提出利用全相位FFT(all-phase FFT,apFFT)简单、有效地校正I/Q正交性幅相误差的新方法。在分析apFFT输入数据形式的基础上,与以往仿真直接设置-(N-1)~N-1点数据作为apFFT输入不同,提出利用矩阵束前向外推得到apFFT的输入数据。经apFFT处理后,求取I/Q通道信号的初相位误差即为相位误差,求传统FFT谱峰之比即为幅度误差。通过计算机仿真验证了前向外推的可靠性以及apFFT求I/Q正交性幅相误差的精度,在3 dB信噪比,镜像抑制度达到60 dB。 相似文献
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宽带I/Q正交解调器是高分辨率SAR系统的关键部件之一。本文讨论了宽带I/Q正交解调器对高分辨SAR系统性能的影响,分析了其主要误差来源,给出了设计原则,介绍了具体电路的设计过程,并给出实验结果。实验表明,该解调器用于高分辨SAR系统是有效的。 相似文献
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由模拟器件构成的宽带正交解调接收机会由于正交通道的幅相不一致性造成整个系统的失真,进而影响整个接收系统的性能。本文仔细分析了幅相误差对接收机性能的影响,提出了基于FIR滤波的一种数字域校正的方法。通过计算机彷真,证实了该方法的可行性。 相似文献
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A Fast and Precise Blind I/Q Mismatch Compensation for Image Rejection in Direct‐Conversion Receiver
In this paper, we propose a new digital blind in‐phase/quadrature‐phase (I/Q) mismatch compensation technique for image rejection in a direct‐conversion receiver (DCR). The proposed image‐rejection circuit adopts DC offset cancellation and a sign‐sign least mean squares (LMS) algorithm with a unique step size adaptation both for a fast and precise I/Q mismatch estimation. In addition, several performance‐optimizing design considerations related to accuracy, speed, and hardware simplicity are discussed. The implementation of the proposed circuit in an FPGA results in an image‐rejection ratio (IRR) of 65 dB, which is the best performance with modulated signals, along with an adaptation time of 0.9 seconds, which is a tenfold increase in the compensation speed as compared to previously reported circuits. The proposed technique will be a promising solution in the area of image rejection to increase both the speed and accuracy of future DCRs. 相似文献
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在当前许多复杂调制射频信号源中,随着数字基带信号越来越多的加入.需要正交凋制器将其调制到需要的载波信号上。正交调制器原理简单:将生成好的I/Q两路基带信号调制到两路正交的载波上,合路后输出。但是在实现时,想获得好的指标就需要考虑载波相位误差,I/Q基带信号幅度不平衡以及载波泄漏等问题。文章给出了一种正交调制器的校准方案,可以减少和模拟以上三种现象造成的调制误差,并给出自动校准和手动校准两种方法。 相似文献
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设计了中频窄带数字正交接收机,该正交接收机是基于PCI结构,带有一路AD及一片AD6620数字下变频处理芯片,用PC机可以方便实时地进行控制.实验结果表明该接收机结构简单、易于实现,而且精度高、误差小. 相似文献
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Orthogonal frequency division multiplexing (OFDM) systems with direct-conversion receiver (DCR) are vulnerable to carrier frequency offset (CFO), dc offset (DCO) and in-phase/quadrature (I/Q) imbalance. In this paper, we propose blind estimator for joint estimation of CFO, DCO and I/Q imbalance in OFDM systems with DCR. Simulation results show that performance of proposed estimator approaches Cramér-Rao lower bound (CRLB) asymptotically, which demonstrates its effectiveness. 相似文献
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ADAPTIVE CALIBRATION OF I AND Q MISMATCH IN QUADRATURE RECEIVER 总被引:2,自引:0,他引:2
The mismatch of in-phase and quadrature channels in quadrature receiver affects and constrains radar detection performance in coherent radar.It is necessary to keep the in-phase and quadrature branches symmetrical.In this letter,an adaptive method to detect imbalance parameters is derived by means of evaluating channel errors from the received signal sequences.No matter how the bias degree of the gain and phase errors in I/Q channels are ,the proposed adaptive scheme can obtain good calibration results.And the required calculations are only a few multiplications and additions.No need of a special test signal,the introduced method is simple to implement and easy to operate. 相似文献