ft8_lib/ft8/encode_v2.h
2018-11-02 15:43:10 +02:00

34 lines
1.3 KiB
C++

#pragma once
#include <stdint.h>
namespace ft8_v2 {
constexpr int ND = 58; // Data symbols
constexpr int NS = 21; // Sync symbols (3 @ Costas 7x7)
constexpr int NN = NS+ND; // Total channel symbols (79)
// Generate FT8 tone sequence from payload data
// [IN] payload - 9 byte array consisting of 72 bit payload
// [OUT] itone - array of NN (79) bytes to store the generated tones (encoded as 0..7)
void genft8(const uint8_t *payload, uint8_t *itone);
// Encode an 87-bit message and return a 174-bit codeword.
// The generator matrix has dimensions (87,87).
// The code is a (174,87) regular ldpc code with column weight 3.
// The code was generated using the PEG algorithm.
// After creating the codeword, the columns are re-ordered according to
// "colorder" to make the codeword compatible with the parity-check matrix
// Arguments:
// * message - array of 87 bits stored as 11 bytes (MSB first)
// * codeword - array of 174 bits stored as 22 bytes (MSB first)
void encode174(const uint8_t *message, uint8_t *codeword);
// Compute 14-bit CRC for a sequence of given number of bits
// [IN] message - byte sequence (MSB first)
// [IN] num_bits - number of bits in the sequence
uint16_t ft8_crc(uint8_t *message, int num_bits);
};