现象：芯片计算出来的有效值波动较大，最大最小值偏差59%。抓了ADC输入信号是稳定的。均方根算法验证过是正确的，带入固定数据算得也是对的。采样方式：软件触发，0.625ms使能1次，共采集16次，在定时器中使能 ADC_EnableSoftwareStartConv(ADC,ENABLE);
AD读取方式：AD中断里读取ADC_GetDat(ADC);


初始化：
void ADC_Initial(void)
{

          ErrorStatus HSIStartUpStatus;
          ADC_InitType ADC_InitStructure;
       
    NVIC_InitType NVIC_InitStructure;

    /* Configure and enable ADC interrupt */
    NVIC_InitStructure.NVIC_IRQChannel                   = ADC_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPriority           = 1;
    NVIC_InitStructure.NVIC_IRQChannelCmd                = ENABLE;
    NVIC_Init(&NVIC_InitStructure);       
       
       
    /* Enable ADC clocks */
    RCC_EnableAHBPeriphClk(RCC_AHB_PERIPH_ADC, ENABLE);
    /* enable ADC 1M clock */
    RCC_EnableHsi(ENABLE);
    /* Wait til1 HSI is ready*/
    HSIStartUpStatus = RCC_WaitHsiStable();
    if(HSIStartUpStatus == SUCCESS)
    {
    }
    else
    {
        /* If HSI fails to start-up, the application will have wrong clock configuration. User can add here some code to deal with this error*/
        /* Go to infinitel1oop*/
        while(1)
        {
        }
    }
    RCC_ConfigAdc1mClk(RCC_ADC1MCLK_SRC_HSI, RCC_ADC1MCLK_DIV8);
    /* RCC_ADCHCLK_DIV16*/
    ADC_ConfigClk(ADC_CTRL3_CKMOD_AHB, RCC_ADCHCLK_DIV16);       
       

    /* ADC configuration ------------------------------------------------------*/
    ADC_InitStructure.MultiChEn      = ENABLE;
    ADC_InitStructure.ContinueConvEn = DISABLE;
    ADC_InitStructure.ExtTrigSelect  = ADC_EXT_TRIGCONV_NONE;
    ADC_InitStructure.DatAlign       = ADC_DAT_ALIGN_R;
    ADC_InitStructure.ChsNumber      = 1;
    ADC_Init(ADC, &ADC_InitStructure);

    /* ADC regular channels configuration */
    ADC_ConfigRegularChannel(ADC, ADC_CH_4_PA4, 1, ADC_SAMP_TIME_29CYCLES5);
//    ADC_ConfigRegularChannel(ADC, ADC_CH_5_PA5, 2, ADC_SAMP_TIME_29CYCLES5);

    /* Regular discontinuous mode channel number configuration */
    ADC_ConfigDiscModeChannelCount(ADC, 1);
    /* Enable regular discontinuous mode */
    ADC_EnableDiscMode(ADC, ENABLE);
       
    /* Enable interrupt */
    ADC_ConfigInt(ADC, ADC_INT_ENDC, ENABLE);
               
                ADC_EnableVrefint(ENABLE);

    /* Enable ADC */
    ADC_Enable(ADC, ENABLE);

    /*wait ADC is ready to use*/
    while(!ADC_GetFlagStatusNew(ADC, ADC_FLAG_RDY))
        ;
    /*wait ADC is powered on*/
    while(ADC_GetFlagStatusNew(ADC, ADC_FLAG_PD_RDY))
        ;       
}