DSP设计--语音压缩(4)

OutData6[i] = alaw2linear(SourData6[i]); }

for(i=0;i<65535;i++) { OutData7[i] = alaw2linear(SourData7[i]); }

for(i=0;i<65535;i++) { OutData8[i] = alaw2linear(SourData8[i]); }

for(i=0;i<65535;i++) { OutData9[i] = alaw2linear(SourData9[i]); }

for(i=0;i<65535;i++) { OutData10[i] = alaw2linear(SourData10[i]); }

for(i=0;i<65535;i++) { OutData11[i] = alaw2linear(SourData11[i]); }

for(i=0;i<65535;i++) { OutData12[i] = alaw2linear(SourData12[i]); }

for(i=0;i<65535;i++) { OutData13[i] = alaw2linear(SourData13[i]); }

for(i=0;i<65535;i++) { OutData14[i] = alaw2linear(SourData14[i]); }

for(i=0;i<65535;i++) { OutData15[i] = alaw2linear(SourData15[i]); }

for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData1[i]);回放程序

}

for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData2[i]); }

for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData3[i]); } for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData4[i]); }

for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData5[i]); }

for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData6[i]); } for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData7[i]); }

for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData8[i]); }

for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData9[i]); } for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {};

MCBSP_write16(hMcbsp,OutData10[i]); } for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData11[i]); } for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData12[i]); } for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData13[i]); } for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData14[i]); } for(i=0;i<65535;i++) { while(!MCBSP_xrdy(hMcbsp)) {}; MCBSP_write16(hMcbsp,OutData15[i]); } break; default: break; } } }

/*****a律压缩******/

unsigned char data2alaw(s16 pcm_val) {

Int mask; Int seg;

unsigned char aval; if (pcm_val >= 0) {

mask = 0xD5; // 标记 (7th) bit = 1 } else

{

mask = 0x55; // 标记 bit = 0 pcm_val = -pcm_val; }

// Convert the scaled magnitude to segment number. seg = search(pcm_val, seg_end, 8);

// Combine the sign, segment, and quantization bits.

if (seg >= 8) // out of range, 返回最大数.

return (0x7F ^ mask);

else {

aval = seg << SEG_SHIFT; if (seg < 2)

aval |= (pcm_val >> 1) & QUANT_MASK; else

aval |= (pcm_val >>seg) & QUANT_MASK; return (aval ^ mask); } }

/*****a律解压******/

int alaw2data(unsigned char a_val) {

Int t; Int seg;

a_val ^= 0x55;

t = (a_val & QUANT_MASK) << 4;

seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT; if(seg==0) {

t += 8; t=(t>>3); }

if((seg<4)&&(seg>0)) {

t +=0x108; t=(t>>(4-seg)); }

if(seg>3) {

t+=0x108;

t=(t<<=(seg-4)); }

return ((a_val & SIGN_BIT) ? t : -t); }

2.实验结果的波形如下： 输入波形：

压缩波形：

输出波形：

3.硬件实现及现象

运行编写的程序会看到DSK板上的3个灯依次点亮，在我们的试验设计中主要通过LED0来指示，当LED0灯亮时，开始在输入端采集音频信号，采集完后，LED0灯灭，在输出端的耳机开始放音，就会听到刚才储存的10秒左右的音频信号。放完音后，LED0灯又重新点亮，随即又开始录音，一直循环下去。

五、 设计（安装）与调试的体会

1、 xx（0921xxx）：

通过这次的DSP实验，让我充分认识到了我的不足。我虽然学习过C语言的编程，但一旦将它应用到实际的比较专业的问题上，我所

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