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Christopher Young 2015-09-21 13:01:18 -04:00
rodzic 229df30ff4
commit a8e8562e5f
1 zmienionych plików z 320 dodań i 317 usunięć
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101
dump978/dump978.c
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@ -36,7 +36,8 @@ static void read_from_stdin(void);
static int process_buffer(uint16_t *phi, int len, uint64_t offset); static int process_buffer(uint16_t *phi, int len, uint64_t offset);
static int demod_adsb_frame(uint16_t *phi, uint8_t *to, int *rs_errors); static int demod_adsb_frame(uint16_t *phi, uint8_t *to, int *rs_errors);
static int demod_uplink_frame(uint16_t *phi, uint8_t *to, int *rs_errors); static int demod_uplink_frame(uint16_t *phi, uint8_t *to, int *rs_errors);
static void demod_frame(uint16_t *phi, uint8_t *frame, int bytes, int16_t center_dphi); static void demod_frame(uint16_t *phi, uint8_t *frame, int bytes,
int16_t center_dphi);
static void handle_adsb_frame(uint64_t timestamp, uint8_t *frame, int rs); static void handle_adsb_frame(uint64_t timestamp, uint8_t *frame, int rs);
static void handle_uplink_frame(uint64_t timestamp, uint8_t *frame, int rs); static void handle_uplink_frame(uint64_t timestamp, uint8_t *frame, int rs);
@ -49,8 +50,7 @@ static void handle_uplink_frame(uint64_t timestamp, uint8_t *frame, int rs);
#ifdef USE_SIGNED_OVERFLOW #ifdef USE_SIGNED_OVERFLOW
#define phi_difference(from, to) ((int16_t)((to) - (from))) #define phi_difference(from, to) ((int16_t)((to) - (from)))
#else #else
inline int16_t phi_difference(uint16_t from, uint16_t to) inline int16_t phi_difference(uint16_t from, uint16_t to) {
{
int32_t difference = to - from; // lies in the range -65535 .. +65535 int32_t difference = to - from; // lies in the range -65535 .. +65535
if (difference >= 32768) // +32768..+65535 if (difference >= 32768) // +32768..+65535
return difference - 65536; // -> -32768..-1: always in range return difference - 65536; // -> -32768..-1: always in range
@ -62,8 +62,7 @@ inline int16_t phi_difference(uint16_t from, uint16_t to)
#endif #endif
#ifndef BUILD_LIB #ifndef BUILD_LIB
int main(int argc, char **argv) int main(int argc, char **argv) {
{
make_atan2_table(); make_atan2_table();
init_fec(); init_fec();
read_from_stdin(); read_from_stdin();
@ -71,16 +70,15 @@ int main(int argc, char **argv)
} }
#else #else
static CallBack userCB = NULL; static CallBack userCB = NULL;
void Dump978Init(CallBack cb) void Dump978Init(CallBack cb) {
{
make_atan2_table(); make_atan2_table();
init_fec(); init_fec();
userCB = cb; userCB = cb;
} }
#endif #endif
static void dump_raw_message(char updown, uint8_t *data, int len, int rs_errors) static void dump_raw_message(char updown, uint8_t *data, int len,
{ int rs_errors) {
#ifndef BUILD_LIB #ifndef BUILD_LIB
int i; int i;
@ -97,22 +95,21 @@ static void dump_raw_message(char updown, uint8_t *data, int len, int rs_errors)
#endif #endif
} }
static void handle_adsb_frame(uint64_t timestamp, uint8_t *frame, int rs) static void handle_adsb_frame(uint64_t timestamp, uint8_t *frame, int rs) {
{ dump_raw_message('-', frame, (frame[0] >> 3) == 0 ? SHORT_FRAME_DATA_BYTES
dump_raw_message('-', frame, (frame[0]>>3) == 0 ? SHORT_FRAME_DATA_BYTES : LONG_FRAME_DATA_BYTES, rs); : LONG_FRAME_DATA_BYTES,
rs);
fflush(stdout); fflush(stdout);
} }
static void handle_uplink_frame(uint64_t timestamp, uint8_t *frame, int rs) static void handle_uplink_frame(uint64_t timestamp, uint8_t *frame, int rs) {
{
dump_raw_message('+', frame, UPLINK_FRAME_DATA_BYTES, rs); dump_raw_message('+', frame, UPLINK_FRAME_DATA_BYTES, rs);
fflush(stdout); fflush(stdout);
} }
uint16_t iqphase[65536]; // contains value [0..65536) -> [0, 2*pi) uint16_t iqphase[65536]; // contains value [0..65536) -> [0, 2*pi)
void make_atan2_table(void) void make_atan2_table(void) {
{
unsigned i, q; unsigned i, q;
union { union {
uint8_t iq[2]; uint8_t iq[2];
@ -123,18 +120,20 @@ void make_atan2_table(void)
for (q = 0; q < 256; ++q) { for (q = 0; q < 256; ++q) {
double d_i = (i - 127.5); double d_i = (i - 127.5);
double d_q = (q - 127.5); double d_q = (q - 127.5);
double ang = atan2(d_q, d_i) + M_PI; // atan2 returns [-pi..pi], normalize to [0..2*pi] double ang = atan2(d_q, d_i) +
M_PI; // atan2 returns [-pi..pi], normalize to [0..2*pi]
double scaled_ang = round(32768 * ang / M_PI); double scaled_ang = round(32768 * ang / M_PI);
u.iq[0] = i; u.iq[0] = i;
u.iq[1] = q; u.iq[1] = q;
iqphase[u.iq16] = (scaled_ang < 0 ? 0 : scaled_ang > 65535 ? 65535 : (uint16_t)scaled_ang); iqphase[u.iq16] =
(scaled_ang < 0 ? 0 : scaled_ang > 65535 ? 65535
: (uint16_t)scaled_ang);
} }
} }
} }
static void convert_to_phi(uint16_t *buffer, int n) static void convert_to_phi(uint16_t *buffer, int n) {
{
int i; int i;
for (i = 0; i < n; ++i) for (i = 0; i < n; ++i)
@ -142,8 +141,7 @@ static void convert_to_phi(uint16_t *buffer, int n)
} }
#ifndef BUILD_LIB #ifndef BUILD_LIB
void read_from_stdin(void) void read_from_stdin(void) {
{
char buffer[65536 * 2]; char buffer[65536 * 2];
int n; int n;
int used = 0; int used = 0;
@ -167,8 +165,7 @@ void read_from_stdin(void)
// #define DEFAULT_SAMPLE_RATE 2048000 // #define DEFAULT_SAMPLE_RATE 2048000
// #define DEFAULT_BUF_LENGTH (262144) 16*16384 // #define DEFAULT_BUF_LENGTH (262144) 16*16384
static char buffer[65536 * 2]; // 131072, max received should be 113120 static char buffer[65536 * 2]; // 131072, max received should be 113120
int process_data(char *data, int dlen) int process_data(char *data, int dlen) {
{
int n; int n;
int processed; int processed;
int doffset = 0; int doffset = 0;
@ -196,10 +193,8 @@ int process_data(char *data, int dlen)
} }
#endif #endif
// Return 1 if word is "equal enough" to expected // Return 1 if word is "equal enough" to expected
static inline int sync_word_fuzzy_compare(uint64_t word, uint64_t expected) static inline int sync_word_fuzzy_compare(uint64_t word, uint64_t expected) {
{
uint64_t diff; uint64_t diff;
if (word == expected) if (word == expected)
@ -262,8 +257,7 @@ static inline int sync_word_fuzzy_compare(uint64_t word, uint64_t expected)
// that matches the sync word 'pattern'. Place the dphi // that matches the sync word 'pattern'. Place the dphi
// threshold to use for bit slicing in '*center'. Return 1 // threshold to use for bit slicing in '*center'. Return 1
// if the sync word is OK, 0 on failure // if the sync word is OK, 0 on failure
int check_sync_word(uint16_t *phi, uint64_t pattern, int16_t *center) int check_sync_word(uint16_t *phi, uint64_t pattern, int16_t *center) {
{
int i; int i;
int32_t dphi_zero_total = 0; int32_t dphi_zero_total = 0;
int zero_bits = 0; int zero_bits = 0;
@ -305,15 +299,15 @@ int check_sync_word(uint16_t *phi, uint64_t pattern, int16_t *center)
} }
} }
//fprintf(stdout, "check_sync_word: center=%.0fkHz, errors=%d\n", *center * 2083334.0 / 65536 / 1000, error_bits); // fprintf(stdout, "check_sync_word: center=%.0fkHz, errors=%d\n", *center *
// 2083334.0 / 65536 / 1000, error_bits);
return (error_bits <= MAX_SYNC_ERRORS); return (error_bits <= MAX_SYNC_ERRORS);
} }
#define SYNC_MASK ((((uint64_t)1) << SYNC_BITS) - 1) #define SYNC_MASK ((((uint64_t)1) << SYNC_BITS) - 1)
int process_buffer(uint16_t *phi, int len, uint64_t offset) int process_buffer(uint16_t *phi, int len, uint64_t offset) {
{
uint64_t sync0 = 0, sync1 = 0; uint64_t sync0 = 0, sync1 = 0;
int lenbits; int lenbits;
int bit; int bit;
@ -360,7 +354,8 @@ int process_buffer(uint16_t *phi, int len, uint64_t offset)
// errors. // errors.
// check for downlink frames: // check for downlink frames:
if (sync_word_fuzzy_compare(sync0, ADSB_SYNC_WORD) || sync_word_fuzzy_compare(sync1, ADSB_SYNC_WORD)) { if (sync_word_fuzzy_compare(sync0, ADSB_SYNC_WORD) ||
sync_word_fuzzy_compare(sync1, ADSB_SYNC_WORD)) {
int startbit = (bit - SYNC_BITS + 1); int startbit = (bit - SYNC_BITS + 1);
int shift = (sync_word_fuzzy_compare(sync0, ADSB_SYNC_WORD) ? 0 : 1); int shift = (sync_word_fuzzy_compare(sync0, ADSB_SYNC_WORD) ? 0 : 1);
int index = startbit * 2 + shift; int index = startbit * 2 + shift;
@ -384,7 +379,8 @@ int process_buffer(uint16_t *phi, int len, uint64_t offset)
} }
// check for uplink frames: // check for uplink frames:
else if (sync_word_fuzzy_compare(sync0, UPLINK_SYNC_WORD) || sync_word_fuzzy_compare(sync1, UPLINK_SYNC_WORD)) { else if (sync_word_fuzzy_compare(sync0, UPLINK_SYNC_WORD) ||
sync_word_fuzzy_compare(sync1, UPLINK_SYNC_WORD)) {
int startbit = (bit - SYNC_BITS + 1); int startbit = (bit - SYNC_BITS + 1);
int shift = (sync_word_fuzzy_compare(sync0, UPLINK_SYNC_WORD) ? 0 : 1); int shift = (sync_word_fuzzy_compare(sync0, UPLINK_SYNC_WORD) ? 0 : 1);
int index = startbit * 2 + shift; int index = startbit * 2 + shift;
@ -413,18 +409,26 @@ int process_buffer(uint16_t *phi, int len, uint64_t offset)
// demodulate 'bytes' bytes from samples at 'phi' into 'frame', // demodulate 'bytes' bytes from samples at 'phi' into 'frame',
// using 'center_dphi' as the bit slicing threshold // using 'center_dphi' as the bit slicing threshold
static void demod_frame(uint16_t *phi, uint8_t *frame, int bytes, int16_t center_dphi) static void demod_frame(uint16_t *phi, uint8_t *frame, int bytes,
{ int16_t center_dphi) {
while (--bytes >= 0) { while (--bytes >= 0) {
uint8_t b = 0; uint8_t b = 0;
if (phi_difference(phi[0], phi[1]) > center_dphi) b |= 0x80; if (phi_difference(phi[0], phi[1]) > center_dphi)
if (phi_difference(phi[2], phi[3]) > center_dphi) b |= 0x40; b |= 0x80;
if (phi_difference(phi[4], phi[5]) > center_dphi) b |= 0x20; if (phi_difference(phi[2], phi[3]) > center_dphi)
if (phi_difference(phi[6], phi[7]) > center_dphi) b |= 0x10; b |= 0x40;
if (phi_difference(phi[8], phi[9]) > center_dphi) b |= 0x08; if (phi_difference(phi[4], phi[5]) > center_dphi)
if (phi_difference(phi[10], phi[11]) > center_dphi) b |= 0x04; b |= 0x20;
if (phi_difference(phi[12], phi[13]) > center_dphi) b |= 0x02; if (phi_difference(phi[6], phi[7]) > center_dphi)
if (phi_difference(phi[14], phi[15]) > center_dphi) b |= 0x01; b |= 0x10;
if (phi_difference(phi[8], phi[9]) > center_dphi)
b |= 0x08;
if (phi_difference(phi[10], phi[11]) > center_dphi)
b |= 0x04;
if (phi_difference(phi[12], phi[13]) > center_dphi)
b |= 0x02;
if (phi_difference(phi[14], phi[15]) > center_dphi)
b |= 0x01;
*frame++ = b; *frame++ = b;
phi += 16; phi += 16;
} }
@ -436,8 +440,7 @@ static void demod_frame(uint16_t *phi, uint8_t *frame, int bytes, int16_t center
// number of corrected errors, or 9999 if demodulation failed. // number of corrected errors, or 9999 if demodulation failed.
// Return 0 if demodulation failed, or the number of bits (not // Return 0 if demodulation failed, or the number of bits (not
// samples) consumed if demodulation was OK. // samples) consumed if demodulation was OK.
static int demod_adsb_frame(uint16_t *phi, uint8_t *to, int *rs_errors) static int demod_adsb_frame(uint16_t *phi, uint8_t *to, int *rs_errors) {
{
int16_t center_dphi; int16_t center_dphi;
int frametype; int frametype;
@ -462,8 +465,7 @@ static int demod_adsb_frame(uint16_t *phi, uint8_t *to, int *rs_errors)
// number of corrected errors, or 9999 if demodulation failed. // number of corrected errors, or 9999 if demodulation failed.
// Return 0 if demodulation failed, or the number of bits (not // Return 0 if demodulation failed, or the number of bits (not
// samples) consumed if demodulation was OK. // samples) consumed if demodulation was OK.
static int demod_uplink_frame(uint16_t *phi, uint8_t *to, int *rs_errors) static int demod_uplink_frame(uint16_t *phi, uint8_t *to, int *rs_errors) {
{
int16_t center_dphi; int16_t center_dphi;
uint8_t interleaved[UPLINK_FRAME_BYTES]; uint8_t interleaved[UPLINK_FRAME_BYTES];
@ -472,7 +474,8 @@ static int demod_uplink_frame(uint16_t *phi, uint8_t *to, int *rs_errors)
return 0; return 0;
} }
demod_frame(phi + SYNC_BITS*2, interleaved, UPLINK_FRAME_BYTES, center_dphi); demod_frame(phi + SYNC_BITS * 2, interleaved, UPLINK_FRAME_BYTES,
center_dphi);
// deinterleave and correct // deinterleave and correct
if (correct_uplink_frame(interleaved, to, rs_errors) == 1) if (correct_uplink_frame(interleaved, to, rs_errors) == 1)