tab_cpt.h

来自「zigbee 飞思卡尔 音频传输 基于ucos的所有源码」· C头文件 代码 · 共 45 行

extern int SIN_TAB[4];	//620Hz
 
 /******************************************************
 * The table holds the coefficients for      *
 * the CPT generator, computed as follows              *
 *                                                     *
 *           sin(2pi*f/fs)*2^31	                       *
 *                                                     *
 * with  fs = 8000Hz  (sampling frequency)             *
 *       f  = 350, 440, 480, 620Hz    				   *
 *                                                     *
 ******************************************************/

 extern int TONES_TAB[24];	//620Hz
         			             		   
         			
/******************************************************
* The table assembles the coefficients and  *
* initial conditions for the difference equations of  *
* the digital sinusoidal oscillators.                 *
*                                                     *
* In general:                                         *
*   DEQ:    y(n) = 2*cos(2pi*f/fs)*y(n-1) - y(n-2)    *
*   I.C.:   y(-1) = 0                                 *
*           y(-2) = -A*sin(2pi*f/fs)                  *
*   where   A  = desired amplitude of sine wave       *
*           f  = desired frequency of sine wave       *
*           fs = sampling frequency                   *
* In this table, y(-2) is always 0. After invoking    *
* power_level.s, it is modified to -A*sin(2pi*f/fs)   *
* Example:                                            *
*       .word    cos(2pi*f/fs)*2^31	    ;coefficient  *
*       .word    0			            ; y(-1)       *
*       .word    0	                    ; y(-2)       *
*                                                     *
******************************************************/         			
           			  
extern short offset_dial[7];
	 	   				
extern short offset_ringback[7];
					    	
extern short offset_busy_reorder[7];
							   
extern int amplitude[3];