在Vivado中使用FPGA进行频率和占空比的测量,可以使用间接测量法。下面是一个基于VHDL的仿真代码示例:

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity Frequency_DutyCycle_Measurement is
  generic (
    CLK_FREQ : integer := 100000000;  -- 输入时钟频率
    MEASURE_TIME : integer := 1000     -- 测量时间(以时钟周期为单位)
  );
  port (
    signal_in : in std_logic;          -- 输入方波脉冲信号
    frequency_out : out integer;       -- 输出频率
    duty_cycle_out : out real          -- 输出占空比
  );
end Frequency_DutyCycle_Measurement;

architecture Behavioral of Frequency_DutyCycle_Measurement is
  signal signal_count : integer range 0 to MEASURE_TIME;
  signal last_signal : std_logic := '0';
  signal signal_high_count : integer range 0 to MEASURE_TIME;
  signal signal_low_count : integer range 0 to MEASURE_TIME;
begin
  process (signal_in)
  begin
    if rising_edge(signal_in) then
      if last_signal = '0' then
        signal_high_count <= signal_high_count + 1;
      end if;
    elsif falling_edge(signal_in) then
      if last_signal = '1' then
        signal_low_count <= signal_low_count + 1;
      end if;
    end if;
    last_signal <= signal_in;
  end process;

  process (clk)
  begin
    if rising_edge(clk) then
      signal_count <= signal_count + 1;
      if signal_count = MEASURE_TIME then
        frequency_out <= signal_high_count / (MEASURE_TIME / CLK_FREQ);
        duty_cycle_out <= to_real(signal_high_count) / to_real(signal_high_count + signal_low_count);
        signal_count <= 0;
        signal_high_count <= 0;
        signal_low_count <= 0;
      end if;
    end if;
  end process;
end Behavioral;

上述代码定义了一个名为Frequency_DutyCycle_Measurement的实体,其中包含一个输入端口signal_in(方波脉冲信号)和两个输出端口frequency_out(频率)和duty_cycle_out(占空比)。

Behavioral架构中,首先通过两个过程分别计算方波脉冲信号的高电平个数和低电平个数。然后,使用另一个过程在每个时钟周期上对高电平和低电平进行计数,并在达到指定的测量时间后计算频率和占空比。最后,将计算结果分别赋值给输出端口frequency_outduty_cycle_out

请注意,上述代码只是一个仿真代码示例,实际在FPGA中使用时需要根据具体的硬件平台和时钟频率进行适当的修改和调整


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