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Integrated EARLYLATE and GARDNER into one loop, tested only EARLYLATE

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This commit is contained in:
ha7ilm 2017-03-06 23:00:34 +01:00
parent 09c873c13d
commit 79a33b0d24
3 changed files with 33 additions and 59 deletions
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2
csdr.c
View file

@ -2376,7 +2376,7 @@ int main(int argc, char *argv[])
timing_recovery_state_t state = timing_recovery_init(algorithm, decimation, add_q);
int debug_i=0;
state.debug_writefiles = 1;
state.debug_writefiles = 0;
state.debug_force = !!debug_n; //should remove that later
FREAD_C;
for(;;)

89
libcsdr.c
View file

@ -1698,6 +1698,7 @@ timing_recovery_state_t timing_recovery_init(timing_recovery_algorithm_t algorit
to_return.debug_force = 0;
to_return.debug_writefiles = 0;
to_return.last_correction_offset = 0;
to_return.earlylate_ratio = 0.25; //0..0.5
return to_return;
}
@ -1717,58 +1718,14 @@ void timing_recovery_cc(complexf* input, complexf* output, int input_size, timin
int num_samples_bit = state->decimation_rate;
int num_samples_halfbit = state->decimation_rate / 2;
int num_samples_quarterbit = state->decimation_rate / 4;
int num_samples_earlylate_wing = num_samples_bit * state->earlylate_ratio;
int debug_i = state->debug_count;
float error;
int el_point_left_index, el_point_right_index, el_point_mid_index;
int si;
if(state->debug_force) fprintf(stderr, "disp(\"begin timing_recovery_cc\");\n");
if(MTIMINGR_HDEBUG) fprintf(stderr, "timing_recovery_cc started, nsb = %d, nshb = %d, nsqb = %d\n", num_samples_bit, num_samples_halfbit, num_samples_quarterbit);
if(state->algorithm == TIMING_RECOVERY_ALGORITHM_GARDNER)
{
for(si=0;;si++)
{
if(current_bitstart_index + num_samples_halfbit * 3 >= input_size) break;
int el_point_left_index = current_bitstart_index + num_samples_quarterbit * 3;
int el_point_right_index = current_bitstart_index + num_samples_quarterbit * 1 - correction_offset;
int el_point_mid_index = current_bitstart_index + num_samples_halfbit;
output[si++] = input[current_bitstart_index + num_samples_halfbit];
error = (
iof(input, current_bitstart_index + num_samples_halfbit * 3) - iof(input, current_bitstart_index + num_samples_halfbit)
) * iof(input, current_bitstart_index + num_samples_halfbit * 2);
if(state->use_q)
{
error += (
qof(input, current_bitstart_index + num_samples_halfbit * 3) - qof(input, current_bitstart_index + num_samples_halfbit)
) * qof(input, current_bitstart_index + num_samples_halfbit * 2);
error /= 2;
}
if( state->debug_force || (state->debug_phase >= si && debug_i) )
{
debug_i--;
if(!debug_i) state->debug_phase = -1;
octave_plot_point_on_cplxsig(input+current_bitstart_index, state->decimation_rate*2,
error,
current_bitstart_index,
correction_offset,
state->debug_writefiles,
3, //number of points to draw below:
num_samples_halfbit * 1, 'r',
num_samples_halfbit * 2, 'r',
num_samples_halfbit * 3, 'r',
0); //last argument is dummy, for the comma
}
if(MTIMINGR_HDEBUG) fprintf(stderr, "current_bitstart_index = %d, error = %g\n", current_bitstart_index, error);
//hey, this should be fixed here:
correction_offset = num_samples_halfbit * (-error/2);
current_bitstart_index += num_samples_bit + correction_offset;
//current_bitstart_index += num_samples_bit + ((error)?((error>0)?1:-1):0);
if(MTIMINGR_HDEBUG) fprintf(stderr, "new current_bitstart_index = %d\n", current_bitstart_index);
if(si>=input_size) { break; }
}
}
else if(state->algorithm == TIMING_RECOVERY_ALGORITHM_EARLYLATE)
{
//bitstart index should be at symbol edge, maximum effect point is at current_bitstart_index + num_samples_halfbit
for(si=0;;si++)
{
//the MathWorks style algorithm has correction_offset.
@ -1782,23 +1739,35 @@ void timing_recovery_cc(complexf* input, complexf* output, int input_size, timin
if(MTIMINGR_HDEBUG) fprintf(stderr, "correction_offset = %d, reset to 0!\n", correction_offset);
correction_offset = 0;
}
//should check if the sign of the correction_offset (or disabling it) has an effect on the EVM.
//it is also a possibility to disable multiplying with the magnitude
int el_point_left_index = current_bitstart_index + num_samples_quarterbit * 3;
int el_point_right_index = current_bitstart_index + num_samples_quarterbit * 1 - correction_offset;
int el_point_mid_index = current_bitstart_index + num_samples_halfbit;
output[si++] = input[current_bitstart_index + el_point_mid_index];
//should check if the sign of the correction_offset (or disabling it) has an effect on the EVM.
//it is also a possibility to disable multiplying with the magnitude
if(state->algorithm == TIMING_RECOVERY_ALGORITHM_EARLYLATE)
{
//bitstart index should be at symbol edge, maximum effect point is at current_bitstart_index + num_samples_halfbit
el_point_right_index = current_bitstart_index + num_samples_earlylate_wing * 3;
el_point_left_index = current_bitstart_index + num_samples_earlylate_wing * 1 - correction_offset;
el_point_mid_index = current_bitstart_index + num_samples_halfbit;
output[si++] = input[current_bitstart_index + el_point_mid_index];
}
else if(state->algorithm == TIMING_RECOVERY_ALGORITHM_GARDNER)
{
//maximum effect point is at current_bitstart_index
el_point_right_index = current_bitstart_index + num_samples_halfbit * 3;
el_point_left_index = current_bitstart_index + num_samples_halfbit * 1;
el_point_mid_index = current_bitstart_index + num_samples_halfbit * 2;
output[si++] = input[current_bitstart_index + num_samples_halfbit * 1];
}
else break;
error = ( iof(input, el_point_left_index) - iof(input, el_point_right_index)) * iof(input, el_point_mid_index);
error = ( iof(input, el_point_right_index) - iof(input, el_point_left_index)) * iof(input, el_point_mid_index);
if(state->use_q)
{
error += ( qof(input, el_point_left_index) - qof(input, el_point_right_index)) * qof(input, el_point_mid_index);
error += ( qof(input, el_point_right_index) - qof(input, el_point_left_index)) * qof(input, el_point_mid_index);
error /= 2;
}
//Correction method #1: this version can only move a single sample in any direction
//Original correction method: this version can only move a single sample in any direction
//current_bitstart_index += num_samples_halfbit * 2 + (error)?((error<0)?1:-1):0;
//Correction method #2: this can move in proportional to the error
if(error>2) error=2;
if(error<-2) error=-2;
if( state->debug_force || (state->debug_phase >= si && debug_i) )
@ -1811,12 +1780,16 @@ void timing_recovery_cc(complexf* input, complexf* output, int input_size, timin
correction_offset,
state->debug_writefiles,
3,
num_samples_quarterbit * 1, 'r',
num_samples_quarterbit, 'r',
num_samples_quarterbit * 2, 'r',
num_samples_quarterbit * 3, 'r',
//el_point_left_index - current_bitstart_index, 'r',
//el_point_right_index - current_bitstart_index, 'r',
//el_point_mid_index - current_bitstart_index, 'r',
0);
}
correction_offset = num_samples_halfbit * (error/2);
int error_sign = (state->algorithm == TIMING_RECOVERY_ALGORITHM_GARDNER) ? -1 : 1;
correction_offset = num_samples_halfbit * error_sign * (error/2);
current_bitstart_index += num_samples_bit + correction_offset;
if(si>=input_size)
{

1
libcsdr.h
View file

@ -308,6 +308,7 @@ typedef struct timing_recovery_state_s
int debug_force;
int debug_writefiles;
int last_correction_offset;
float earlylate_ratio;
} timing_recovery_state_t;
timing_recovery_state_t timing_recovery_init(timing_recovery_algorithm_t algorithm, int decimation_rate, int use_q);