dtmf.cpp

DTMF软解码C实现.rar

#include <string.h>
#include <stdlib.h>


//
// DTMF 解码程序
// author: hendry
// date: 2008/11
//

//
// 注意：1) 采样率 4000 bps（采样率很低，降低对系统要求，解码准确度一点不含糊，(*^__^*) 嘻嘻……) 
//
//      2) 采样精度 8bit, signed char, 注意是 “有符号数”啊!! 千万别搞错了, 如果输入无符号数，哭去吧.. 
//
//      3) 每输入 50 个采样点就得到一次 DTMF 解码，历时 12.5ms, 国标要求 DTMF 码持续时间 >= 40ms, 因此连续解码的话可以得到连续3个相同码值，实际上，我就是这样提高抗干扰性的。 
//
//     4) 属于本人原创，请勿用作商用，否则保留追究权利。 
//
// by hendry, 2008/11 
//

unsigned char	s_dtmf_p;
long			s_dtmf_real[8];
long			s_dtmf_image[8];

const unsigned char g_sincos_len = 50;
const signed char g_cos_table[400] = {(signed char)0x7E,(signed char)0x3A,(signed char)0xB7,(signed char)0x83,(signed char)0xD7,(signed char)0x57,(signed char)0x79,(signed char)0x18,(signed char)0x9D,(signed char)0x8D,(signed char)0xFA,(signed char)0x6D,(signed char)0x6A,(signed char)0xF4,(signed char)0x8B,(signed char)0xA1,(signed char)0x1E,(signed char)0x7A,(signed char)0x52,(signed char)0xD1,(signed char)0x83,(signed char)0xBC,(signed char)0x3F,(signed char)0x7E,(signed char)0x34,(signed char)0xB2,(signed char)0x84,(signed char)0xDD,(signed char)0x5B,(signed char)0x77,(signed char)0x12,(signed char)0x99,(signed char)0x90,(signed char)0x00,(signed char)0x70,(signed char)0x67,(signed char)0xEE,(signed char)0x89,(signed char)0xA5,(signed char)0x24,
(signed char)0x7C,(signed char)0x4E,(signed char)0xCB,(signed char)0x82,(signed char)0xC1,(signed char)0x44,(signed char)0x7D,(signed char)0x2F,(signed char)0xAD,(signed char)0x86,(signed char)0x7E,(signed char)0x2D,(signed char)0xA1,(signed char)0x91,(signed char)0x10,(signed char)0x7B,(signed char)0x47,(signed char)0xB8,(signed char)0x86,(signed char)0xF2,(signed char)0x70,(signed char)0x5D,(signed char)0xD2,(signed char)0x82,(signed char)0xD5,(signed char)0x60,(signed char)0x6E,(signed char)0xEE,(signed char)0x85,(signed char)0xBB,(signed char)0x4A,(signed char)0x7A,(signed char)0x0C,(signed char)0x8F,(signed char)0xA4,(signed char)0x30,(signed char)0x7E,(signed char)0x29,(signed char)0x9F,(signed char)0x93,
(signed char)0x14,(signed char)0x7B,(signed char)0x44,(signed char)0xB4,(signed char)0x87,(signed char)0xF6,(signed char)0x72,(signed char)0x5A,(signed char)0xCE,(signed char)0x82,(signed char)0xD9,(signed char)0x62,(signed char)0x6C,(signed char)0xEA,(signed char)0x84,(signed char)0xBE,(signed char)0x4D,(signed char)0x78,(signed char)0x08,(signed char)0x8D,(signed char)0x7E,(signed char)0x1D,(signed char)0x8F,(signed char)0xAF,(signed char)0x4B,(signed char)0x74,(signed char)0xEA,(signed char)0x82,(signed char)0xDC,(signed char)0x6D,(signed char)0x56,(signed char)0xBA,(signed char)0x8A,(signed char)0x0F,(signed char)0x7D,(signed char)0x2B,(signed char)0x96,(signed char)0xA5,(signed char)0x3F,(signed char)0x79,
(signed char)0xF8,(signed char)0x84,(signed char)0xCF,(signed char)0x65,(signed char)0x60,(signed char)0xC7,(signed char)0x86,(signed char)0x01,(signed char)0x7B,(signed char)0x38,(signed char)0x9F,(signed char)0x9B,(signed char)0x33,(signed char)0x7C,(signed char)0x06,(signed char)0x87,(signed char)0xC2,(signed char)0x5C,(signed char)0x69,(signed char)0xD4,(signed char)0x83,(signed char)0xF3,(signed char)0x77,(signed char)0x44,(signed char)0xA9,(signed char)0x94,(signed char)0x25,(signed char)0x7E,(signed char)0x14,(signed char)0x8C,(signed char)0x7E,(signed char)0x0C,(signed char)0x84,(signed char)0xDD,(signed char)0x75,(signed char)0x38,(signed char)0x95,(signed char)0xB4,(signed char)0x5D,(signed char)0x5D,
(signed char)0xB4,(signed char)0x95,(signed char)0x38,(signed char)0x76,(signed char)0xDE,(signed char)0x84,(signed char)0x0B,(signed char)0x7E,(signed char)0x0C,(signed char)0x84,(signed char)0xDD,(signed char)0x75,(signed char)0x39,(signed char)0x95,(signed char)0xB3,(signed char)0x5D,(signed char)0x5E,(signed char)0xB5,(signed char)0x94,(signed char)0x37,(signed char)0x76,(signed char)0xDF,(signed char)0x84,(signed char)0x0A,(signed char)0x7E,(signed char)0x0D,(signed char)0x84,(signed char)0xDC,(signed char)0x75,(signed char)0x39,(signed char)0x96,(signed char)0xB3,(signed char)0x5C,(signed char)0x5E,(signed char)0xB5,(signed char)0x94,(signed char)0x37,(signed char)0x76,(signed char)0xDF,(signed char)0x84,
(signed char)0x7E,(signed char)0xD7,(signed char)0x9C,(signed char)0x69,(signed char)0x20,(signed char)0x82,(signed char)0x31,(signed char)0x5E,(signed char)0x92,(signed char)0xE9,(signed char)0x7D,(signed char)0xC7,(signed char)0xA8,(signed char)0x72,(signed char)0x0F,(signed char)0x85,(signed char)0x41,(signed char)0x51,(signed char)0x8B,(signed char)0xFA,(signed char)0x79,(signed char)0xB8,(signed char)0xB6,(signed char)0x78,(signed char)0xFD,(signed char)0x8A,(signed char)0x4F,(signed char)0x43,(signed char)0x85,(signed char)0x0C,(signed char)0x73,(signed char)0xAA,(signed char)0xC5,(signed char)0x7C,(signed char)0xEB,(signed char)0x91,(signed char)0x5C,(signed char)0x33,(signed char)0x83,(signed char)0x1E,
(signed char)0x6A,(signed char)0x9E,(signed char)0xD5,(signed char)0x7E,(signed char)0xDA,(signed char)0x9B,(signed char)0x68,(signed char)0x23,(signed char)0x82,(signed char)0x2F,(signed char)0x7E,(signed char)0xC1,(signed char)0xC2,(signed char)0x7E,(signed char)0xBF,(signed char)0xC3,(signed char)0x7E,(signed char)0xBE,(signed char)0xC5,(signed char)0x7E,(signed char)0xBC,(signed char)0xC6,(signed char)0x7E,(signed char)0xBB,(signed char)0xC8,(signed char)0x7E,(signed char)0xBA,(signed char)0xC9,(signed char)0x7E,(signed char)0xB9,(signed char)0xCA,(signed char)0x7E,(signed char)0xB7,(signed char)0xCC,(signed char)0x7D,(signed char)0xB6,(signed char)0xCD,(signed char)0x7D,(signed char)0xB5,(signed char)0xCF,
(signed char)0x7D,(signed char)0xB3,(signed char)0xD0,(signed char)0x7D,(signed char)0xB2,(signed char)0xD2,(signed char)0x7D,(signed char)0xB1,(signed char)0xD3,(signed char)0x7C,(signed char)0xB0,(signed char)0xD5,(signed char)0x7C,(signed char)0xAE,(signed char)0xD6,(signed char)0x7C,(signed char)0xAD,(signed char)0xD8,(signed char)0x7B,(signed char)0xAC,(signed char)0x7E,(signed char)0xAA,(signed char)0xF7,(signed char)0x62,(signed char)0x83,(signed char)0x48,(signed char)0x1B,(signed char)0x93,(signed char)0x79,(signed char)0xC8,(signed char)0xD3,(signed char)0x75,(signed char)0x8E,(signed char)0x27,(signed char)0x3D,(signed char)0x86,(signed char)0x6A,(signed char)0xEB,(signed char)0xB4,(signed char)0x7D,
(signed char)0xA1,(signed char)0x03,(signed char)0x5A,(signed char)0x82,(signed char)0x52,(signed char)0x0F,(signed char)0x9A,(signed char)0x7C,(signed char)0xBD,(signed char)0xDF,(signed char)0x6F,(signed char)0x89,(signed char)0x33,(signed char)0x32,(signed char)0x89,(signed char)0x70,(signed char)0xDE,(signed char)0xBE,(signed char)0x7C,(signed char)0x9A,(signed char)0x10,(signed char)0x51,(signed char)0x82,(signed char)0x5B,(signed char)0x02,(signed char)0xA2,(signed char)0x7D,(signed char)0xB3,(signed char)0xEC,(signed char)0x69,(signed char)0x7E,(signed char)0x96,(signed char)0x33,(signed char)0x14,(signed char)0xAB,(signed char)0x7A,(signed char)0x88,(signed char)0x4F,(signed char)0xF3,(signed char)0xC6,
(signed char)0x6D,(signed char)0x82,(signed char)0x65,(signed char)0xD4,(signed char)0xE5,(signed char)0x5A,(signed char)0x85,(signed char)0x75,(signed char)0xB7,(signed char)0x05,(signed char)0x40,(signed char)0x8F,(signed char)0x7D,(signed char)0x9F,(signed char)0x25,(signed char)0x22,(signed char)0xA1,(signed char)0x7D,(signed char)0x8E,(signed char)0x43,(signed char)0x02,(signed char)0xBA,(signed char)0x74,(signed char)0x84,(signed char)0x5C,(signed char)0xE2,(signed char)0xD7,(signed char)0x63,(signed char)0x82,(signed char)0x6F,(signed char)0xC3,(signed char)0xF7,(signed char)0x4C,(signed char)0x89,(signed char)0x7B,(signed char)0xA9,(signed char)0x17,(signed char)0x30,(signed char)0x98,(signed char)0x7E
};
const signed char g_sin_table[400] = {(signed char)0x00,(signed char)0x70,(signed char)0x67,(signed char)0xEE,(signed char)0x89,(signed char)0xA5,(signed char)0x24,(signed char)0x7C,(signed char)0x4E,(signed char)0xCC,(signed char)0x82,(signed char)0xC1,(signed char)0x44,(signed char)0x7D,(signed char)0x2F,(signed char)0xAD,(signed char)0x86,(signed char)0xE2,(signed char)0x5F,(signed char)0x75,(signed char)0x0C,(signed char)0x96,(signed char)0x93,(signed char)0x06,(signed char)0x73,(signed char)0x63,(signed char)0xE8,(signed char)0x87,(signed char)0xA9,(signed char)0x29,(signed char)0x7D,(signed char)0x49,(signed char)0xC6,(signed char)0x82,(signed char)0xC6,(signed char)0x49,(signed char)0x7D,(signed char)0x29,(signed char)0xA9,(signed char)0x87,
(signed char)0xE8,(signed char)0x63,(signed char)0x73,(signed char)0x06,(signed char)0x93,(signed char)0x96,(signed char)0x0C,(signed char)0x75,(signed char)0x5F,(signed char)0xE2,(signed char)0x00,(signed char)0x76,(signed char)0x53,(signed char)0xC5,(signed char)0x83,(signed char)0xE3,(signed char)0x68,(signed char)0x67,(signed char)0xE1,(signed char)0x83,(signed char)0xC7,(signed char)0x55,(signed char)0x75,(signed char)0xFE,(signed char)0x89,(signed char)0xAE,(signed char)0x3D,(signed char)0x7D,(signed char)0x1B,(signed char)0x97,(signed char)0x9A,(signed char)0x21,(signed char)0x7D,(signed char)0x37,(signed char)0xAA,(signed char)0x8C,(signed char)0x04,(signed char)0x77,(signed char)0x50,(signed char)0xC2,
(signed char)0x84,(signed char)0xE6,(signed char)0x6A,(signed char)0x65,(signed char)0xDD,(signed char)0x82,(signed char)0xCA,(signed char)0x58,(signed char)0x74,(signed char)0xFA,(signed char)0x88,(signed char)0xB1,(signed char)0x40,(signed char)0x7C,(signed char)0x18,(signed char)0x95,(signed char)0x9C,(signed char)0x25,(signed char)0x7E,(signed char)0x34,(signed char)0x00,(signed char)0x7B,(signed char)0x38,(signed char)0x9F,(signed char)0x9B,(signed char)0x32,(signed char)0x7C,(signed char)0x07,(signed char)0x87,(signed char)0xC1,(signed char)0x5C,(signed char)0x69,(signed char)0xD5,(signed char)0x83,(signed char)0xF2,(signed char)0x77,(signed char)0x45,(signed char)0xA9,(signed char)0x93,(signed char)0x25,
(signed char)0x7E,(signed char)0x15,(signed char)0x8C,(signed char)0xB5,(signed char)0x52,(signed char)0x70,(signed char)0xE2,(signed char)0x82,(signed char)0xE4,(signed char)0x71,(signed char)0x50,(signed char)0xB4,(signed char)0x8D,(signed char)0x17,(signed char)0x7E,(signed char)0x23,(signed char)0x92,(signed char)0xAA,(signed char)0x46,(signed char)0x76,(signed char)0xF0,(signed char)0x83,(signed char)0xD6,(signed char)0x6A,(signed char)0x5B,(signed char)0xC0,(signed char)0x88,(signed char)0x09,(signed char)0x7C,(signed char)0x31,(signed char)0x00,(signed char)0x7D,(signed char)0x17,(signed char)0x87,(signed char)0xD2,(signed char)0x71,(signed char)0x43,(signed char)0x9C,(signed char)0xAB,(signed char)0x55,
(signed char)0x65,(signed char)0xBE,(signed char)0x8F,(signed char)0x2D,(signed char)0x79,(signed char)0xE9,(signed char)0x82,(signed char)0xFF,(signed char)0x7D,(signed char)0x18,(signed char)0x87,(signed char)0xD2,(signed char)0x70,(signed char)0x43,(signed char)0x9C,(signed char)0xAA,(signed char)0x54,(signed char)0x65,(signed char)0xBF,(signed char)0x8F,(signed char)0x2D,(signed char)0x79,(signed char)0xEA,(signed char)0x82,(signed char)0xFF,(signed char)0x7D,(signed char)0x18,(signed char)0x87,(signed char)0xD1,(signed char)0x70,(signed char)0x44,(signed char)0x9C,(signed char)0xAA,(signed char)0x54,(signed char)0x65,(signed char)0xBF,(signed char)0x8F,(signed char)0x2C,(signed char)0x7A,(signed char)0xEB,
(signed char)0x00,(signed char)0x77,(signed char)0xB3,(signed char)0xBA,(signed char)0x7A,(signed char)0xF7,(signed char)0x8C,(signed char)0x54,(signed char)0x3E,(signed char)0x84,(signed char)0x12,(signed char)0x70,(signed char)0xA6,(signed char)0xCA,(signed char)0x7D,(signed char)0xE5,(signed char)0x94,(signed char)0x60,(signed char)0x2E,(signed char)0x82,(signed char)0x23,(signed char)0x67,(signed char)0x9A,(signed char)0xDA,(signed char)0x7E,(signed char)0xD4,(signed char)0x9E,(signed char)0x6B,(signed char)0x1D,(signed char)0x83,(signed char)0x34,(signed char)0x5C,(signed char)0x91,(signed char)0xEC,(signed char)0x7C,(signed char)0xC4,(signed char)0xAA,(signed char)0x73,(signed char)0x0B,(signed char)0x86,
(signed char)0x44,(signed char)0x4F,(signed char)0x8A,(signed char)0xFD,(signed char)0x78,(signed char)0xB5,(signed char)0xB8,(signed char)0x79,(signed char)0xFA,(signed char)0x8B,(signed char)0x00,(signed char)0x6D,(signed char)0x92,(signed char)0x02,(signed char)0x6C,(signed char)0x92,(signed char)0x03,(signed char)0x6B,(signed char)0x91,(signed char)0x05,(signed char)0x6A,(signed char)0x90,(signed char)0x06,(signed char)0x6A,(signed char)0x8F,(signed char)0x08,(signed char)0x69,(signed char)0x8F,(signed char)0x09,(signed char)0x68,(signed char)0x8E,(signed char)0x0B,(signed char)0x67,(signed char)0x8D,(signed char)0x0D,(signed char)0x66,(signed char)0x8D,(signed char)0x0E,(signed char)0x65,(signed char)0x8C,
(signed char)0x10,(signed char)0x64,(signed char)0x8B,(signed char)0x11,(signed char)0x63,(signed char)0x8B,(signed char)0x13,(signed char)0x62,(signed char)0x8A,(signed char)0x14,(signed char)0x61,(signed char)0x8A,(signed char)0x16,(signed char)0x60,(signed char)0x89,(signed char)0x18,(signed char)0x5F,(signed char)0x89,(signed char)0x19,(signed char)0x5E,(signed char)0x00,(signed char)0x5C,(signed char)0x82,(signed char)0x4F,(signed char)0x12,(signed char)0x98,(signed char)0x7B,(signed char)0xC0,(signed char)0xDC,(signed char)0x71,(signed char)0x8A,(signed char)0x30,(signed char)0x35,(signed char)0x88,(signed char)0x6E,(signed char)0xE2,(signed char)0xBB,(signed char)0x7C,(signed char)0x9C,(signed char)0x0C,
(signed char)0x53,(signed char)0x82,(signed char)0x58,(signed char)0x06,(signed char)0xA0,(signed char)0x7D,(signed char)0xB6,(signed char)0xE8,(signed char)0x6B,(signed char)0x86,(signed char)0x3B,(signed char)0x29,(signed char)0x8D,(signed char)0x74,(signed char)0xD6,(signed char)0xC6,(signed char)0x79,(signed char)0x95,(signed char)0x19,(signed char)0x4A,(signed char)0x83,(signed char)0x61,(signed char)0xF9,(signed char)0xA8,(signed char)0x7E,(signed char)0xAC,(signed char)0xF5,(signed char)0x64,(signed char)0x84,(signed char)0x46,(signed char)0x00,(signed char)0x45,(signed char)0x8D,(signed char)0x7C,(signed char)0xA3,(signed char)0x20,(signed char)0x27,(signed char)0x9E,(signed char)0x7D,(signed char)0x90,
(signed char)0x3E,(signed char)0x07,(signed char)0xB5,(signed char)0x76,(signed char)0x85,(signed char)0x58,(signed char)0xE7,(signed char)0xD2,(signed char)0x67,(signed char)0x82,(signed char)0x6C,(signed char)0xC8,(signed char)0xF1,(signed char)0x50,(signed char)0x88,(signed char)0x79,(signed char)0xAD,(signed char)0x12,(signed char)0x35,(signed char)0x95,(signed char)0x7E,(signed char)0x97,(signed char)0x31,(signed char)0x16,(signed char)0xAA,(signed char)0x7A,(signed char)0x89,(signed char)0x4D,(signed char)0xF5,(signed char)0xC5,(signed char)0x6E,(signed char)0x82,(signed char)0x64,(signed char)0xD6,(signed char)0xE3,(signed char)0x5B,(signed char)0x84,(signed char)0x74,(signed char)0xB9,(signed char)0x03
};



//
// dtmf decode initiation
//
void init_dtmf_decoder()
{
	s_dtmf_p = 0;
	memset(s_dtmf_real, 0, sizeof(long) * 8);
	memset(s_dtmf_image, 0, sizeof(long) * 8);
}

long labs (long n)
{
  return (n < 0 ? -n : n);
}


//
// dtmf decode program
//
// input: sample = DTMF wave sample value, 
//        sample rate = 4000 point per second
//		  NOTE!! sample is "SIGNED" char, NOT "UNSIGNED" char !!
// output: 0 = decoded not completed yet
//		   '0123456789*#ABCD' = dtmf code
//
unsigned char decode_dtmf(signed char sample)
{
	unsigned char	i, low_freq, high_freq;
	unsigned short	offset;
	
	for (i = 0, offset = s_dtmf_p; i < 8; i ++, offset += g_sincos_len)
	{
		s_dtmf_real[i] += sample * g_cos_table[offset];
		s_dtmf_image[i] += sample * g_sin_table[offset];
	}

	s_dtmf_p ++;

	if (s_dtmf_p == g_sincos_len)	// 50 sample has inputed, let's look at the result...
	{
		// calculate |R| + |I|
		for (i = 0; i < 8; i ++)
		{
			s_dtmf_real[i] = labs(s_dtmf_real[i]) + labs(s_dtmf_image[i]);