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90 lines (65 loc) · 2.29 KB
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/*
This C program demonstrates the construction of AX.25 frames.
It is intended to serve as a reference for the communication standard design of HyacinthSat.
Part 3: AFSK baseband Modulator
Version: 0.0.1 Date: April 22, 2025
Developer & Acknowledgments:
BG7ZDQ - Implemented the program
BI4PYM - Suggestions & review
License: MIT License
*/
#include <stdio.h>
#include <stdint.h>
#include "header.h"
// 获取外部变量
extern uint16_t Stream_Len;
extern uint8_t Bitstream[65536];
// 声明内部函数
int AFSK_300_Modulation();
int AFSK_600_Modulation();
int AFSK_1200_Modulation();
int AFSK_2400_Modulation();
int AFSK_Modulator(double SPACE_TONE, double MARK_TONE, uint16_t BAUD_RATE);
// AFSK 300bd 基带调制函数
int AFSK_300_Modulation(){
double SPACE_TONE = 1900; // 空号 (0)
double MARK_TONE = 1600; // 传号 (1)
uint16_t BAUD_RATE = 300; // 波特率
return AFSK_Modulator(SPACE_TONE, MARK_TONE, BAUD_RATE);
}
// AFSK 600bd 基带调制函数
int AFSK_600_Modulation(){
double SPACE_TONE = 1930; // 空号 (0)
double MARK_TONE = 1470; // 传号 (1)
uint16_t BAUD_RATE = 600; // 波特率
return AFSK_Modulator(SPACE_TONE, MARK_TONE, BAUD_RATE);
}
// AFSK 1200bd 基带调制函数
int AFSK_1200_Modulation(){
double SPACE_TONE = 2200; // 空号 (0)
double MARK_TONE = 1200; // 传号 (1)
uint16_t BAUD_RATE = 1200; // 波特率
return AFSK_Modulator(SPACE_TONE, MARK_TONE, BAUD_RATE);
}
// AFSK 2400bd 基带调制函数
int AFSK_2400_Modulation(){
double SPACE_TONE = 2600; // 空号 (0)
double MARK_TONE = 800; // 传号 (1)
uint16_t BAUD_RATE = 2400; // 波特率
return AFSK_Modulator(SPACE_TONE, MARK_TONE, BAUD_RATE);
}
// AFSK 基础基带调制函数
int AFSK_Modulator(double SPACE_TONE, double MARK_TONE, uint16_t BAUD_RATE){
double symbol_duration = 1000.0 / BAUD_RATE;
printf("APRS %d bd\n", BAUD_RATE);
WAV_Initialization();
for (int i = 0; i < Stream_Len; i++){
if (Bitstream[i] == 1){
WAV_Write(MARK_TONE, symbol_duration);
} else {
WAV_Write(SPACE_TONE, symbol_duration);
}
}
WAV_Finalization();
return 0;
}