#include "fsk.h"
-#include "freedv_vhf_framing.h"
#include "tdma.h"
#include <stdint.h>
#include <assert.h>
#include <stdbool.h>
/* Easy handle to enable/disable a whole slew of debug printouts */
-//#define VERY_DEBUG 1
+#define VERY_DEBUG 1
static const uint8_t TDMA_UW_V[] = {0,1,1,0,0,1,1,1,
1,0,1,0,1,1,0,1};
+static const uint8_t TDMA_UW_D[] = {1,1,1,1,0,0,0,1,
+ 1,1,1,1,1,1,0,0};
+
+static const uint8_t * TDMA_UW_LIST_A[] = {&TDMA_UW_V,&TDMA_UW_D};
+
tdma_t * tdma_create(struct TDMA_MODE_SETTINGS mode){
tdma_t * tdma;
tdma->ignore_rx_on_tx = true;
tdma->sync_misses = 0;
+ /* Set up the UWs we use for this mode. */
+ if(mode.frame_type == TDMA_FRAME_A){
+ tdma->uw_types = 2;
+ tdma->uw_list = TDMA_UW_LIST_A;
+ tdma->master_bit_pos = 35;
+ }
/* Allocate buffer for incoming samples */
/* TODO: We may only need a single slot's worth of samps -- look into this */
samp_buffer = (COMP *) malloc(sizeof(COMP)*slot_size*Ts*(n_slots+1));
return NULL;
}
-void tdma_print_stuff(tdma_t * tdma){
- printf("symrate: %d\n",tdma->settings.sym_rate);
- printf("fsk_m: %d\n",tdma->settings.fsk_m);
- printf("samprate: %d\n",tdma->settings.samp_rate);
- printf("slotsize: %d\n",tdma->settings.slot_size);
- printf("framesize: %d\n",tdma->settings.frame_size);
- printf("nslots: %d\n",tdma->settings.n_slots);
- printf("frametype: %d\n",tdma->settings.frame_type);
- printf("sync_offset: %ld\n",tdma->sample_sync_offset);
-}
-
void tdma_destroy(tdma_t * tdma){
slot_t * slot = tdma->slots;
slot_t * next_slot;
return slot_size * (Fs/Rs);
}
+/* Search for a complete UW in a buffer of bits */
+size_t tdma_search_uw(tdma_t * tdma, u8 bits[], size_t nbits, size_t * delta_out, size_t * uw_type_out){
+/*size_t fvhff_search_uw(const uint8_t bits[],size_t nbits,
+ const uint8_t uw[], size_t uw_len,
+ size_t * delta_out, size_t bits_per_sym){*/
+
+ size_t uw_len = tdma->settings.uw_len;
+ size_t bits_per_sym = (tdma->settings.fsk_m==2)?1:2;
+ u8 ** uw_list = tdma->uw_list;
+ size_t ibits,iuw;
+ size_t delta_min = uw_len;
+ size_t delta;
+ size_t j;
+ size_t uw_type_min;
+ size_t uw_delta_min = uw_len;
+ size_t offset_min,uw_offset_min;
+ /* Check each UW */
+ for(j = 0; j < tdma->uw_types; j++){
+ /* Walk through buffer bits */
+ u8 * uw = uw_list[j];
+ size_t offset_min = 0;
+ for(ibits = 0; ibits < nbits-uw_len; ibits+=bits_per_sym){
+ delta = 0;
+ for(iuw = 0; iuw < uw_len; iuw++){
+ if(bits[ibits+iuw] != uw[iuw]) delta++;
+ }
+ if( delta < delta_min ){
+ delta_min = delta;
+ offset_min = ibits;
+ }
+ }
+ if( delta_min < uw_delta_min ){
+ uw_delta_min = delta_min;
+ uw_offset_min = offset_min;
+ uw_type_min = j;
+ }
+ }
+ if(delta_out != NULL) *delta_out = uw_delta_min;
+ if(uw_type_out != NULL) *uw_type_out = uw_type_min;
+ return uw_offset_min;
+}
+
+
/* Convience function to look up a slot from it's index number */
slot_t * tdma_get_slot(tdma_t * tdma, u32 slot_idx){
/* Don't try and index beyond the end */
u8 frame_bits[frame_size_bits];
/* Re-find UW in demod'ed slice */
/* Should probably just be left to tdma_rx_pilot_sync */
- off = fvhff_search_uw(demod_bits,n_demod_bits,TDMA_UW_V,uw_len,&delta,bits_per_sym);
+ //off = fvhff_search_uw(demod_bits,n_demod_bits,TDMA_UW_V,uw_len,&delta,bits_per_sym);
+ off = tdma_search_uw(tdma, demod_bits, n_demod_bits, &delta, NULL);
f_start = off - (frame_size_bits-uw_len)/2;
/* If frame is not fully in demod bit buffer, there's not much we can do */
/* Check to see if this is a master timing frame. */
bool master_mode = false;
- if(tdma->settings.frame_type == FREEDV_VHF_FRAME_AT){
- if(frame_bits[35])
- master_mode = true;
- }
+ if(frame_bits[tdma->master_bit_pos])
+ master_mode = true;
/* Handle counter fiddling for master timing frames */
if(master_mode){
/* Flag to indicate whether or not we should re-do the demodulation */
bool repeat_demod = false;
int rdemod_offset = 0;
- size_t delta,off;
+ size_t delta,off,uw_type;
i32 f_start;
i32 frame_offset;
bool f_valid = false;
/* Demodulate the frame */
fsk_demod(fsk,bit_buf,frame_samps);
- off = fvhff_search_uw(bit_buf,nbits,TDMA_UW_V,uw_len,&delta,bits_per_sym);
+
+ off = tdma_search_uw(tdma, bit_buf, nbits, &delta, &uw_type);
f_start = off- (frame_bits-uw_len)/2;
/* Check frame tolerance and sync state*/
fprintf(stderr,"f_start: %d, Re-demod-ing\n",f_start);
}
if(f_valid){
- fprintf(stderr,"Good UW\n");
+ fprintf(stderr,"Good UW, type %d\n",uw_type);
}else{
fprintf(stderr,"Bad UW\n");
}
/* Unicode underline for pretty printing */
char underline[] = {0xCC,0xB2,0x00};
- fprintf(stderr,"slot: %d fstart:%d offset: %d delta: %d f1:%.3f EbN0:%f\n",tdma->slot_cur,f_start,off,delta,fsk->f_est[0],fsk->EbNodB);
+ fprintf(stderr,"slot: %d fstart:%d offset: %d delta: %d f1:%.3f EbN0:%f\n",
+ tdma->slot_cur,f_start,off,delta,fsk->f_est[0],fsk->EbNodB);
for(i=0; i<nbits; i++){
fprintf(stderr,"%d",bit_buf[i]);
if((i>off && i<=off+uw_len) || i==f_start || i==(f_start+frame_bits-1)){
fprintf(stderr,"\n");
#endif
- /* Update slot offset to compensate for frame centering */
- /* Also check to see if any slots are master. If so, take timing from them */
- i32 offset_total = 0;
- i32 offset_slots = 0;
- i32 offset_master = 0; /* Offset of master slot */
- i32 master_max = 0; /* Highest 'master count' */
- for( i=0; i<n_slots; i++){
- /* Only check offset from valid frames */
- slot_t * i_slot = tdma_get_slot(tdma,i);
- if(i_slot->state == rx_sync){
- i32 local_offset = i_slot->slot_local_frame_offset;
- /* Filter out extreme spurious timing offsets */
- if(abs(local_offset)<(slot_samps/4)){
- #ifdef VERY_DEBUG
- fprintf(stderr,"Local offset: %d\n",local_offset);
- #endif
- offset_total+=local_offset;
- offset_slots++;
- if(i_slot->master_count > master_max){
- master_max = i_slot->master_count;
- offset_master = local_offset;
+ /* If we are in master sync mode, don't adjust demod timing. we ARE demod timing */
+ if(tdma->state != master_sync){
+ /* Update slot offset to compensate for frame centering */
+ /* Also check to see if any slots are master. If so, take timing from them */
+ i32 offset_total = 0;
+ i32 offset_slots = 0;
+ i32 offset_master = 0; /* Offset of master slot */
+ i32 master_max = 0; /* Highest 'master count' */
+ for( i=0; i<n_slots; i++){
+ /* Only check offset from valid frames */
+ slot_t * i_slot = tdma_get_slot(tdma,i);
+ if(i_slot->state == rx_sync){
+ i32 local_offset = i_slot->slot_local_frame_offset;
+ /* Filter out extreme spurious timing offsets */
+ if(abs(local_offset)<(slot_samps/4)){
+ #ifdef VERY_DEBUG
+ fprintf(stderr,"Local offset: %d\n",local_offset);
+ #endif
+ offset_total+=local_offset;
+ offset_slots++;
+ if(i_slot->master_count > master_max){
+ master_max = i_slot->master_count;
+ offset_master = local_offset;
+ }
}
}
}
- }
- offset_total = offset_slots>0 ? offset_total/offset_slots:0;
- /* Use master slot for timing if available, otherwise take average of all frames */
- if(master_max >= mode.mastersat_min){
- tdma->sample_sync_offset += (offset_master/4);
- #ifdef VERY_DEBUG
- fprintf(stderr,"Syncing to master offset %d\n",tdma->sample_sync_offset);
- #endif
- }else{
- tdma->sample_sync_offset += (offset_total/4);
+ offset_total = offset_slots>0 ? offset_total/offset_slots:0;
+ /* Use master slot for timing if available, otherwise take average of all frames */
+ if(master_max >= mode.mastersat_min){
+ tdma->sample_sync_offset += (offset_master/4);
+ #ifdef VERY_DEBUG
+ fprintf(stderr,"Syncing to master offset %d\n",tdma->sample_sync_offset);
+ #endif
+ }else{
+ tdma->sample_sync_offset += (offset_total/4);
+ #ifdef VERY_DEBUG
+ fprintf(stderr,"Total Offset:%d\n",offset_total);
+ fprintf(stderr,"Slot offset: %d of %d\n",tdma->sample_sync_offset,slot_samps*n_slots);
+ #endif
+ }
#ifdef VERY_DEBUG
- fprintf(stderr,"Total Offset:%d\n",offset_total);
- fprintf(stderr,"Slot offset: %d of %d\n",tdma->sample_sync_offset,slot_samps*n_slots);
+ fprintf(stderr,"\n");
#endif
}
- #ifdef VERY_DEBUG
- fprintf(stderr,"\n");
- #endif
-
}
tdma->slot_cur++;
/* Compensate for frame timing offset sliding towards the start of buffer */
/* Do so by running this again, demodulating two slots, and moving the slot offset one slot forward */
if( slot_offset < (slot_samps/4) ){
- tdma->sample_sync_offset = tdma->sample_sync_offset + slot_samps;
- tdma_rx_pilot_sync(tdma);
#ifdef VERY_DEBUG
fprintf(stderr,"Recursing\n");
#endif
+ tdma->sample_sync_offset = tdma->sample_sync_offset + slot_samps;
+ tdma_rx_pilot_sync(tdma);
}
}
fsk_demod(fsk,pilot_bits,&sample_buffer[search_offset_i]);
fsk_demod(fsk,pilot_bits,&sample_buffer[search_offset_i]);
- offset = fvhff_search_uw(pilot_bits,n_pilot_bits,TDMA_UW_V,uw_len,&delta,bits_per_sym);
+ offset = tdma_search_uw(tdma, pilot_bits, n_pilot_bits, &delta, NULL);
f_start = offset - (frame_bits-uw_len)/2;
fprintf(stderr,"delta: %d offset %d so:%d\n",delta,offset,search_offset_i);
#define __CODEC_2_TDMA_H
#include "fsk.h"
-#include "freedv_vhf_framing.h"
#include <stdint.h>
#include <stdbool.h>
#include "comp_prim.h"
+#define TDMA_FRAME_A 3 /* 4800T Frame */
+
/* TODO: Replace these types with their full names */
/* I'm just feeling lazy right now */
typedef uint64_t u64;
/* Declaration of basic 4800bps freedv tdma mode, defined in tdma.h */
//struct TDMA_MODE_SETTINGS FREEDV_4800T;
-#define FREEDV_4800T {2400,4,48000,48,44,2,FREEDV_VHF_FRAME_AT,16,2,2,2,2,6,3,5};
+#define FREEDV_4800T {2400,4,48000,48,44,2,TDMA_FRAME_AT,16,2,2,2,2,6,3,5};
/* Callback typedef that just returns the bits of the frame */
/* TODO: write this a bit better */
-typedef void (*tdma_cb_rx_frame)(u8* frame_bits,u32 slot_i, slot_t * slot, tdma_t * tdma, void * cb_data);
+typedef void (*tdma_cb_rx_frame)(u8* frame_bits,u32 slot_i, slot_t * slot, tdma_t * tdma,u8 uw_type, void * cb_data);
/* Callback typedef when TDMA is ready to schedule a new frame */
/* Returns 1 if a frame is supplied, 0 if not */
void * tx_cb_data;
void * tx_burst_cb_data;
bool ignore_rx_on_tx; /* Don't try and demod samples from a frame in a slot marked as TX */
+
+ size_t master_bit_pos; /* Where in the frame can we find the master indicator bit? */
+ uint8_t uw_types; /* How many different UWs does this framing format use? pulled from frame_type */
+ uint8_t ** uw_list; /* Pointer to list of valid UWs */
+
+
};
*/
void tdma_rx(tdma_t * tdma, COMP * samps,u64 timestamp);
-/* Hideous debug function */
-void tdma_print_stuff(tdma_t * tdma);
-
/* Set the RX callback function */
void tdma_set_rx_cb(tdma_t * tdma,tdma_cb_rx_frame rx_callback,void * cb_data);
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