基于Hilbert变换的单边带调制系统及FPGA实现

SSB Modulation System Based on Hilbert Transformation and FPGA Implementation

为解决单边带调制方法因在载波调制技术中难以实现而不被广泛应用的问题,对单边带调制方法进行了研究,提出了基于Hilbert正交变换的单边带调制算法,以及该算法的FPGA(Field Programmable Gate Arrays)实现。建立了Matlab的系统分析模型,采用DSP Builder设计了单边带调制程序,并通过Modelsim对该程序进行了仿真,得到了理想的单边带调制的波形。仿真结果表明,100阶有限冲击响应滤波器可以理想地逼近Hil-bert变换器。该算法共占用了15%的FPGA系统资源,有效降低了使用成本,并且在声频定向扬声器中获得了实际应用。

Single-sideband modulation has many advantages such as small bandwidth, low-power, etc in carrier modulation techniques. And because of the difficulty of realization, it has not been widely used to- day. We study the method of the single-sideband modulation based on Hilbert transformation, and intro- duces the theoretical background and FPGA（Field Programmable Gate Arrays） implementation of the SSB（Single Sideband Modulation） system. The simulation results of the Matlab model demonstrate that 100 order FIR（Finite Impulse Response filter） finite impulse response filter could approximate the ideal Hilbert convertor. The SSB system based on FPGA was simulated by Modelsim. And the simulation got an ideal single-sideband modulation waveform. The entire SSB system only takes up 15% of the FPGA resources, reducing the costs effectively. And the system was used in audio directional loudspeaker prac- tically.