基于FPGA与Matlab的数字正交解调器的设计

Design of Digital Quadrature Demodulator Based on FPGA and Matlab

摘要:

为有效提取测控系统输入信号的幅度和相位信息,设计了基于FPGA与Matlab的信号数字正交解调器；在Matlab/Simulink环境中产生一路调幅信号,并在此环境下利用5个直接I型的4阶FIR滤波器节搭建了20阶FIR滤波器；利用FPGA查表法实现数控振荡器(NCO),并控制1路调幅信号与正交的正、余弦信号分别进行数字混频处理；对经FPGA数字混频处理后的两路倍频分量和基频分量信号进行滤波处理,经处理后的信号在FPGA的控制下进行相加处理；最后在硬件平台上进行了仿真测试实验,验证了该方案的正确性和可行性。

Abstract:

For extracting the amplitude and phase information of the input signal of the control system effectively, this paper designs a signal digital quadrature demodulator based on FPGA and MATLAB. Producing a signal amplitude and using 5 order FIR filters of 4 stairs to build a order FIR filter of 20 stairs in MATLAB/Simulink environment; realizing a Numerical Controlled Oscillator (NCO) basing on a looking up table method of FPGA, and carrying on a digital mixing process between a amplitude modulation signal and the positive/cosine signals in the control of FPGA; filtering the frequency component signal and the fundamental frequency component signal after the process of digital mixing, then getting two output signals, adding the two output signals. Finally the simulation experiment, which verifies the correctness and feasibility of the scheme, is carried out on the hardware platform.