星载柔性转发器的数字信道化器设计与实现

发布时间：2018-01-11 23:31

本文关键词：星载柔性转发器的数字信道化器设计与实现　出处：《西安电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：作为宽带卫星移动通信系统中的关键技术之一,数字信道化技术在不改变有效载荷结构的前提下,可以准确地提取上行链路信道中各个窄带信号,经星上处理后,可重构出所需的下行链路信号。本文重点研究了星载柔性转发器的数字信道化器,该数字信道化器既可实现均匀带宽信号的交换,又可实现非均匀带宽信号的交换,且具有简单高效的实现结构、良好的灵活性以及较大的容量等特点。本文的主要工作如下:1.给出了一种基于复指数调制滤波器组和多相分解技术的数字信道化器高效实现结构,该结构可正确地完成上行链路信号的分路、交换和重构等星上处理操作,且实现复杂度低。2.针对非均匀带宽数字信道化器中信号重构的特殊需求,提出了一种频率采样法和窗函数法相结合的原型滤波器设计方法,以降低重构信号失真度及减少信道间泄漏。仿真结果表明,该方法能够使原型滤波器获得较大的阻带衰减及较小的通带拼接抖动。3.搭建了一种非均匀带宽数字信道化器的仿真模型。在不同信号调制(BPSK,QPSK和8PSK)方式下,从子信道间功率泄漏、系统误比特率和量化性能等方面,对该数字信道化器的性能进行了仿真分析。结果表明:子信道间的功率泄漏小于-90dB;当误比特率为10-3时,与理想情况相比,该数字信道化器的性能劣化程度小于0.2dB。4.设计了一种数字AGC电路对信号幅值范围进行压缩。由于数字信道化器中电路交换模块和D/A转换模块对输入信号有一定的数据位宽要求,因此采用AGC技术使输入数据稳定在一个确定的动态范围内,从而保证该两个模块的正常工作。仿真结果表明:该数字AGC电路的性能满足系统要求且对非均匀带宽数字信道化器的性能影响较小。5.完成了非均匀带宽数字信道化器的FPGA设计及实现。首先,给出了一种非均匀带宽数字信道化器的FPGA总体设计方案;接着,提出了一种新型的滤波器FPGA设计方法,用于降低滤波器的硬件实现复杂度;最后,对数字信道化器中各个子模块进行了FPGA设计及实现。分析结果表明:该数字信道化器仅仅需要256个乘法器,大大降低了硬件资源的消耗。
[Abstract]:As one of the key technologies of broadband satellite mobile communication system, digital channelized technology without changing the payload structure, can accurately extract the narrowband signals in the uplink channel, via satellite processing, can be reconstructed from the downlink signal is required. This paper focuses on the digital channelizers flexible satellite transponder and the digital channel of device can realize the exchange of uniform bandwidth signal, and can realize the non uniform switching bandwidth signal, and has simple structure and high efficiency, good flexibility and large capacity and so on. The main work of this paper are as follows: 1. the efficient structure of a digital channelizer based on complex index modulation filter and polyphase decomposition technique, which can correctly complete the shunt uplink signal, switching and reconstruction of on-board processing operation, and implementation complexity. According to the special needs of non uniform.2. low bandwidth digital signal channel is reconstructed, puts forward the design method of the prototype filter a frequency sampling method and window function method are combined, in order to reduce the signal distortion and reconstruction to reduce the channel leakage. The simulation results show that this method can make the prototype filter to obtain larger stopband the smaller the pass band attenuation and splicing jitter.3. set up a non-uniform bandwidth digital channelizers simulation model. In different signal modulation (BPSK, QPSK and 8PSK) mode, the inter channel leakage power, bit error rate and quantization performance, the performance of the digital channel is conducted simulation analysis. The results show that the inter channel leakage power is less than -90dB; when the bit error rate is 10-3, compared to the ideal case, deterioration of the digital channel of device performance is less than 0.2dB.4. to design a digital AGC The circuit of the signal amplitude range compression. Because the circuit of digital channelizers switching module and D/A conversion module has certain requirements on the data width of the input signal, so using AGC technology to make the input data stability in a certain dynamic range, so as to ensure the normal work of the two modules. The simulation results show that the the performance of AGC digital circuit to meet the requirements of the system and the effect of non-uniform.5. bandwidth digital channelizers completes the design and implementation of FPGA non uniform bandwidth digital channelizer. Firstly, FPGA gives a general design of non-uniform bandwidth digital channelizers; then, we put forward a new the FPGA filter design method is used to reduce the hardware complexity of the filter; finally, the sub module of digital channelizers in the design and implementation of FPGA. The results showed that the number of The channelizer needs only 256 multipliers, which greatly reduces the consumption of hardware resources.

【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN927.23

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