复信号抽取滤波fpga代码
时间: 2023-07-23 10:37:54 浏览: 51
以下是一个简单的FPGA代码示例,用于对一个复信号进行抽取滤波:
```verilog
module complex_downsampling_filter(
input clk, // 时钟信号
input reset, // 复位信号
input signed [15:0] in_real, // 输入实部
input signed [15:0] in_imag, // 输入虚部
output reg signed [15:0] out_real, // 输出实部
output reg signed [15:0] out_imag // 输出虚部
);
// 常量定义
localparam M = 5; // 抽取因子
localparam L = 20; // 滤波器阶数
// 存储器定义
reg signed [15:0] x_real [0:M-1]; // 输入实部存储器
reg signed [15:0] x_imag [0:M-1]; // 输入虚部存储器
reg signed [15:0] y_real [0:M-1]; // 输出实部存储器
reg signed [15:0] y_imag [0:M-1]; // 输出虚部存储器
// 低通滤波器系数
reg signed [15:0] b [0:L-1] = {16'h0220, 16'h0341, 16'h04b7, 16'h06c7, 16'h095c,
16'h0c7a, 16'h103b, 16'h149e, 16'h19c1, 16'h1f9e,
16'h2632, 16'h2d76, 16'h3553, 16'h3dbd, 16'h46a6,
16'h4ff1, 16'h59a0, 16'h63a1, 16'h6de4, 16'h7864};
// 抽取滤波器
always @(posedge clk) begin
if (reset) begin
// 复位
for (i = 0; i < M; i = i + 1) begin
x_real[i] <= 0;
x_imag[i] <= 0;
y_real[i] <= 0;
y_imag[i] <= 0;
end
out_real <= 0;
out_imag <= 0;
end else begin
// 输入存储
x_real[0] <= in_real;
x_imag[0] <= in_imag;
for (i = 1; i < M; i = i + 1) begin
x_real[i] <= x_real[i-1];
x_imag[i] <= x_imag[i-1];
end
// 滤波器
reg signed [31:0] acc_real;
reg signed [31:0] acc_imag;
acc_real <= 0;
acc_imag <= 0;
for (i = 0; i < L; i = i + 1) begin
acc_real <= acc_real + x_real[i]*b[i];
acc_imag <= acc_imag + x_imag[i]*b[i];
end
// 抽取
for (i = 0; i < M; i = i + 1) begin
y_real[i] <= acc_real;
y_imag[i] <= acc_imag;
end
// 输出
out_real <= y_real[M-1];
out_imag <= y_imag[M-1];
for (i = M-1; i > 0; i = i - 1) begin
y_real[i] <= y_real[i-1];
y_imag[i] <= y_imag[i-1];
end
end
end
endmodule
```
这个代码示例实现了一个抽取因子为5的复信号抽取滤波器,在FPGA中运行。具体实现中,使用了一个20阶的低通滤波器对输入信号进行滤波,并通过抽取器将滤波后的输出进行抽取,得到降采样后的复信号。这个代码示例中使用了Verilog进行实现,其中的存储器和时序逻辑的具体实现方式可能会根据不同的FPGA平台有所不同。