Verilog的costas环的载波同步代码
时间: 2023-10-03 13:05:52 浏览: 53
以下是一个简单的 Verilog Costas环的载波同步器示例代码:
```verilog
module costas_sync(
input clk,
input reset,
input [7:0] in_data,
output [7:0] out_data
);
// 定义常量
parameter N = 8; // 数据位宽
parameter M = 2; // 载波同步环中的延迟元件数
parameter PI_DIV_2 = 1.570796327; // pi/2 的值
// 定义变量
reg [7:0] data_i, data_q; // 输入数据的 I/Q 分量
reg [M:0] i_delay, q_delay; // I/Q 分量的延迟值
reg [7:0] i_out, q_out; // I/Q 分量的输出值
reg [31:0] phase_accum; // 相位累加器
reg [31:0] phase_error; // 相位误差
reg [31:0] phase_adjust; // 相位调整值
reg [1:0] sync_state; // 同步状态
reg [1:0] next_state; // 下一个同步状态
// 初始化
initial begin
i_delay = 2'b0;
q_delay = 2'b0;
phase_accum = 32'h0;
phase_error = 32'h0;
phase_adjust = 32'h0;
sync_state = 2'b00;
end
// 输入数据的 I/Q 分量提取
assign data_i = in_data[7:4];
assign data_q = in_data[3:0];
// I/Q 分量的延迟
always @(posedge clk, negedge reset) begin
if(reset == 1'b0) begin
i_delay <= 2'b0;
q_delay <= 2'b0;
end else begin
i_delay <= {data_i, i_delay[N-1:1]};
q_delay <= {data_q, q_delay[N-1:1]};
end
end
// I/Q 分量的输出
always @(posedge clk, negedge reset) begin
if(reset == 1'b0) begin
i_out <= 8'h0;
q_out <= 8'h0;
end else begin
i_out <= i_delay[M];
q_out <= q_delay[M];
end
end
// 相位误差计算
always @(posedge clk, negedge reset) begin
if(reset == 1'b0) begin
phase_error <= 32'h0;
end else begin
case(sync_state)
2'b00: begin // 未同步状态
phase_error <= 32'h0;
end
2'b01: begin // 搜索状态
phase_error <= phase_accum + (i_out * q_delay[M] - q_out * i_delay[M]);
end
2'b10: begin // 锁定状态
phase_error <= i_out * q_delay[M] - q_out * i_delay[M];
end
endcase
end
end
// 相位累加器
always @(posedge clk, negedge reset) begin
if(reset == 1'b0) begin
phase_accum <= 32'h0;
end else begin
phase_accum <= phase_accum + phase_adjust;
end
end
// 相位调整值计算
always @(posedge clk, negedge reset) begin
if(reset == 1'b0) begin
phase_adjust <= 32'h0;
end else begin
case(sync_state)
2'b00: begin // 未同步状态
phase_adjust <= 32'h0;
end
2'b01: begin // 搜索状态
phase_adjust <= $bitstoreal(phase_error) * PI_DIV_2;
end
2'b10: begin // 锁定状态
phase_adjust <= $bitstoreal(phase_error) * PI_DIV_2 * 0.01;
end
endcase
end
end
// 同步状态机
always @(posedge clk, negedge reset) begin
if(reset == 1'b0) begin
sync_state <= 2'b00;
end else begin
case(sync_state)
2'b00: begin // 未同步状态
if(i_out == 8'h0 && q_out == 8'h0)
next_state <= 2'b00;
else
next_state <= 2'b01;
end
2'b01: begin // 搜索状态
if(i_out == 8'h0 && q_out == 8'h0)
next_state <= 2'b00;
else if(abs(phase_error) < 32'h1000000)
next_state <= 2'b10;
else
next_state <= 2'b01;
end
2'b10: begin // 锁定状态
if(i_out == 8'h0 && q_out == 8'h0)
next_state <= 2'b00;
else if(abs(phase_error) > 32'h1000000)
next_state <= 2'b01;
else
next_state <= 2'b10;
end
endcase
sync_state <= next_state;
end
end
// 输出数据
assign out_data = {i_out, q_out};
endmodule
```