楼 主:pengfan 2004年12月6日21:07

 请问有关采样和DA转换的问题？
我想在单片机中编程模拟一个AD采样后的波形，具体要求如下；
1、模拟的AD转换输入的函数为y＝5sin1000π（x－π/2）+2.5，也就是说这个函数的周期
是2ms,并且y＝5sinx波形向右移动了一个π/2，且向上移动了一个2。5，也就是波形全部在
x轴的上面和y轴的右边了
2、AD转换过程中采样的频率为8K
不知道怎么模拟编程才是正确的，我编写的程序是；Timer0_process() interrupt 1
{ 
    uchar a;
    EA=0;   
    P1_5=!P1_5;                                         //测验
    _nop_();
    P1_5=!P1_5;             
    switch(count)
    {
        case 0:
        {
             TH0=0xFA;
            TL0=0x9A;
            XBYTE[DA_ADDRESS]=B0000_0000;
            count++;
        }break;
        case 1:
        case 14:
        {
             TH0=0xFA;
            TL0=0x9A;
            XBYTE[DA_ADDRESS]=B0010_0000;
            count++;
        }break;
        case 2:
        case 13:
        {
             TH0=0xFA;
            TL0=0x9A;
            XBYTE[DA_ADDRESS]=B0100_0000;
            count++;
        }break;
        case 3:
        case 12:
        {
             TH0=0xFA;
            TL0=0x9A;
            XBYTE[DA_ADDRESS]=B0110_0000 ;
            count++;
        }break;
        case 4:
        case 11:
        {
             TH0=0xFA;
            TL0=0x9A;
            XBYTE[DA_ADDRESS]=B1000_0000 ;
            count++;
        }break;
        case 5:
        case 10:
        {
             TH0=0xFA;
            TL0=0x9A;
            XBYTE[DA_ADDRESS]=B1010_0000;
            count++;
        }break;
        case 6:
        case 9:
        {
             TH0=0xFA;
            TL0=0x9A;
            XBYTE[DA_ADDRESS]=B1100_0000;
            count++;
        }break;
        case 7:
        case 8:
        {
             TH0=0xFA;
            TL0=0x9A;
            XBYTE[DA_ADDRESS]=B1110_0000;
            count++;
        }break;
        case 15:
        {
             TH0=0xFA;
            TL0=0x9A;
            XBYTE[DA_ADDRESS]=B0000_0000;
            count=0;
        };break;
    DOG=!DOG;
    _nop_();
    DOG=!DOG;
    EA=1;
    }
}