试验四FIR滤波器试验

1、实验四 FIR滤波器实验一、实验内容1、掌握TMS320C54x DSPLIB函数库中fir 函数的使用方法。2、学习并掌握5402 DSP片上外设DMA勺结构与配置 。3、使用DM徽据传输方式在C语言下实现直接型的 FIR滤波器。、实验内容1、使用查询方式设计一个fir低通滤波器，通带频率为2400Hz。Fpass=2400,fstop=3000,fs=16000-1D0567FrftMhCiY Q=HZJ#include #include #lnclude #include #include #include void delay(s16 period);HANDLE hHandset;s

2、16 data;/* Create specific data section for coeffiecients */#pragma DATA_SECTION(coeffs,coefficients);/* Low Pass Filter */short coeffs16=2810,985,-906, -2112, -1653,2005,6878, 10556, 10556,6878,2005, -1653, -2112,-906,985,2810;#pragma DATA_SECTION(delaybuff,delay);short delaybuff16=0;short *delaypt

3、r = &(delaybuff0);short inp_buffer1;short out_buffer1;short *inp_ptr=inp_buffer;short *out_ptr=out_buffer;void main() s16 cnt=2;if (brd_init(100) return;/* blink the leds a couple times */ while ( cnt- )brd_led_toggle(BRD_LED0);/* brd_delay_msec(1000); */ delay(1000)-brd_led_toggle(BRD_LED1); /* brd

4、_delay_msec(1000); */ delay(1000);brd_led_toggle(BRD_LED2); /* brd_delay_msec(1000); */ delay(1000);/* Open Handset Codec */* Acquire handle/* DAC in 15-bit/* ADC in 15-bit/* 6dB gain on/* -6dB gain on/* 16KHz sampling ratehHandset = codec_open(HANDSET_CODEC); to codec */* Set codec parameters */cod

5、ec_dac_mode(hHandset, CODEC_DAC_15BIT);mode */codec_adc_mode(hHandset, CODEC_ADC_15BIT);mode */codec_ain_gain(hHandset, CODEC_AIN_6dB);analog input to ADC */codec_aout_gain(hHandset, CODEC_AOUT_MINUS_6dB);analog output from DAC */codec_sample_rate(hHandset,SR_16000);*/* Polling and digital loopback

6、*/ while (1)/* Wait for sample from handset */while (!MCBSP_RRDY(HANDSET_CODEC) ;/* Read sample from and write back to handset codec */ inp_buffer0 = *(volatile u16*)DRR1_ADDR(HANDSET_CODEC);/*数据处理开始*/fir计算fir(inp_ptr,coeffs,out_ptr,&delayptr,16,1);data=out_buffer0&0 xfffe;/*数据处理结束*/*(volatile u16*)

7、DXR1_ADDR(HANDSET_CODEC) =data ;void delay(s16 period)int i, j;for(i=0; iperiod; i+)for(j=0; j1; j+);2.使用DMAT式设计FIR低通滤波器，通带截频为4000Hz。从5402 DSK板白MIC端口输入频率为3000Hz和5000Hz正弦信号的叠力口信号，使用示波器在SPEAKE端口观察输出信号波形。Fpass=4000,fstop=5000,fs=16000_ Magnitude Response (dB),-10-15口-25-3001234567Frequency (kHtz)EB_PhM

8、fi Rsseonss,#include #include #include #include #include void delay(s16 period);extern void DMAC2ISR();HANDLE hHandset;unsigned int dmsefc, dmmcr, dmctr, src_addr, dst_addr;unsigned int dmpre, dmsrcp, dmdstp, dmidx0, dmidx1, dmfri0, dmfri1, dmgsa, dmgda, dmgcr, dmgfr;/* Create specific data section

9、for buffer (symbol, section_name) */#pragma DATA_SECTION(buffer,audio_buffer); int buffer0 x500;/* Create specific data section for coeffiecients */#pragma DATA_SECTION(coeffs,coefficients);/* Low Pass Filter */int coeffs16=560,-1842,-686,1948,-282,-3838,3221,16103, 16103,3221,-3838,-282,1948,-686,-

10、1842,560);#pragma DATA_SECTION(delaybuff,delay);int delaybuff16=0;/* declare and initialize two variables for DMAC ISRs */int frame=0;int flag=0;int temp;int currbuff = 0;/* delayptr holds the address of the start of the delay buffer */int *delayptr1 = &(delaybuff0);void main() s16 cnt=1;/* These ar

11、e the items that BIOS will set when we use it */BSCR = 0 x8806;XPC = 0;PMST = 0 xA0;brd_set_cpu_freq(50);TIMER_HALT(0);brd_set_wait_states(7, 7, 9);TIMER_RESET(0);if(brd_init_bios() return;/* Open Handset Codec */hHandset = codec_open(HANDSET_CODEC);/* Acquire handle tocodec */ /* Set codec paramete

12、rs */* DAC in 15-bit mode*/codec_dac_mode(hHandset, CODEC_DAC_15BIT);/* ADC in 15-bit mode/* 6dB gain on analog/* -6dB gain on analog/* 16KHz sampling rate */codec_adc_mode(hHandset, CODEC_ADC_15BIT);*/codec_ain_gain(hHandset, CODEC_AIN_6dB);input to ADC */codec_aout_gain(hHandset, CODEC_AOUT_MINUS_

13、6dB); output from DAC */codec_sample_rate(hHandset,SR_16000);/* Clear IFR */INTR_CLR_FLAG(DMAC2);/* Reset all DMA channels */ dma_reset_all();/* Initialize DMA channel 2 */dmsefc = (DSYNC_REVT1 12);dmmcr = (AuToINIT_ENABLE 15) | (DINM_ENABLE 14) |(IMOD_HALFBLOCK 13) | (CTMOD_DEC 12) | (INDEXMODE_NOM

14、OD 8) | (SPACE_DATA 6) | (INDEXMODE_INC 2) | (SPACE_DATA);dmctr = 0 xFF;src_addr = DRR1_ADDR(HANDSET_CODEC);dst_addr = (unsigned int) &buffer;dma_init(DMA_CH2, dmsefc, dmmcr, dmctr, SPACE_DA TA, src_addr, SPACE_DATA, dst_addr);/* Set number of frames for channel 2 */DMA_FRAMECOUNT(DMA_CH2, 2);/* Set

15、 up global autoinit registers for DMA CH2 Input */dmgsa = src_addr;dmgda = dst_addr;dmgcr = 0 xFF;dmgfr = 2;/* Set up global priority and enable control register for Ch2 */dmpre = (HIGH_PRIORITY 10) | (INTSEL_01 6);dmsrcp = SPACE_DATA;dmdstp = SPACE_DATA;dmidx0 = 0;dmidx1 = 0;dmfri0 = 0;dmfri1 = 0;d

16、ma_global_init(dmpre, dmsrcp, dmdstp, dmidx0, dmidx1, dmfri0, dmfri1, dmgsa, dmgda, dmgcr, dmgfr);/* Enable channel 2 */DMA_ENABLE(DMA_CH2);/* prime the serial port to begin input buffer stream */temp = *(volatile u16*)DRR1_ADDR(HANDSET_CODEC);/* Enable DMAC2 interrupt */INTR_ENABLE(DMAC2);/* Enable

17、 Global Interrupts */INTR_GLOBAL_ENABLE;/* Endless loop waiting for DMAC2 interrupt */for(;);void delay(s16 period)int i, j;for(i=0; iperiod; i+)for(j=0; j1; j+);三、思考题1、滤波器设计中为什么要设有延迟缓冲存储器delaybuff ?其大小有什么限制？答：在连续的数据块计算时，延迟缓冲区保存着后一次计算所需要的前一次的输出数据。这个缓冲存储区的起点必须位于Kbit的边界处，即起始地址的最低 K=log2nh个有效位必须为零。2、使用查询方式和 DMA断方式设计FIR滤波器时，允许DSP用于数字信号处理程序的最大时间分别是多少？答：查询方式允许 DSP用于数字信号处理程序的最大时间是Ts,而DMA中断方式设计 FIR滤波器时允许用于数字信号处理程序的最大时间是256Ts。3、如何设置C