GARDNER works, but we need a better way to calculate the error
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ha7ilm
parent
306e4aeb91
commit
dde8fa0d08
2 changed files with 35 additions and 22 deletions
54
libcsdr.c
54
libcsdr.c
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@ -1644,7 +1644,7 @@ void pll_cc(pll_t* p, complexf* input, float* output_dphase, complexf* output_nc
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}
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}
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void octave_plot_point_on_cplxsig(complexf* signal, int signal_size, float error, int index, int writefiles, int points_size, ...)
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void octave_plot_point_on_cplxsig(complexf* signal, int signal_size, float error, int index, int correction_offset, int writefiles, int points_size, ...)
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{
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static int figure_output_counter = 0;
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int* points_z = (int*)malloc(sizeof(int)*points_size);
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@ -1668,7 +1668,7 @@ void octave_plot_point_on_cplxsig(complexf* signal, int signal_size, float error
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(char)points_color[i]&0xff, (i<points_size-1)?',':' '
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);
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va_end(vl);
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fprintf(stderr, ");\ntitle(\"index = %d, error = %f\");\nsubplot(2,2,1);\nplot(zsig, isig,\"b-\",", index, error);
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fprintf(stderr, ");\ntitle(\"index = %d, error = %f, cxoffs = %d\");\nsubplot(2,2,1);\nplot(zsig, isig,\"b-\",", index, error, correction_offset);
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for(int i=0;i<points_size;i++)
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fprintf(stderr, "[%d],[%f],\"%c.\"%c",
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points_z[i], iof(signal, points_z[i]),
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@ -1697,7 +1697,7 @@ timing_recovery_state_t timing_recovery_init(timing_recovery_algorithm_t algorit
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to_return.debug_count = 3;
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to_return.debug_force = 0;
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to_return.debug_writefiles = 0;
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//to_return.last_phase_offset = 0;
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to_return.last_correction_offset = 0;
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return to_return;
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}
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@ -1712,6 +1712,7 @@ void timing_recovery_cc(complexf* input, complexf* output, int input_size, timin
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{
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//We always assume that the input starts at center of the first symbol cross before the first symbol.
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//Last time we consumed that much from the input samples that it is there.
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int correction_offset = state->last_correction_offset;
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int current_bitstart_index = 0;
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int num_samples_bit = state->decimation_rate;
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int num_samples_halfbit = state->decimation_rate / 2;
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@ -1744,6 +1745,7 @@ void timing_recovery_cc(complexf* input, complexf* output, int input_size, timin
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octave_plot_point_on_cplxsig(input+current_bitstart_index, state->decimation_rate*2,
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error,
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current_bitstart_index,
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correction_offset,
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state->debug_writefiles,
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3, //number of points to draw below:
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num_samples_halfbit * 1, 'r',
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@ -1756,33 +1758,40 @@ void timing_recovery_cc(complexf* input, complexf* output, int input_size, timin
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if(MTIMINGR_HDEBUG) fprintf(stderr, "new current_bitstart_index = %d\n", current_bitstart_index);
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if(si>=input_size) { break; }
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}
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state->input_processed = current_bitstart_index;
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state->output_size = si;
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}
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else if(state->algorithm == TIMING_RECOVERY_ALGORITHM_EARLYLATE)
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{
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//bitstart index should be at symbol maximum effect point
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for(si=0;;si++)
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{
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//the MathWorks style algorithm has correction_offset.
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//correction_offset = 0;
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if(current_bitstart_index + num_samples_halfbit * 3 >= input_size) break;
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if(MTIMINGR_HDEBUG) fprintf(stderr, "current_bitstart_index = %d, input_size = %d\n",
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current_bitstart_index, input_size);
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if(MTIMINGR_HDEBUG) fprintf(stderr, "current_bitstart_index = %d, input_size = %d, correction_offset(prev) = %d\n",
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current_bitstart_index, input_size, correction_offset);
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if(correction_offset<=-num_samples_quarterbit*0.9 || correction_offset>=0.9*num_samples_quarterbit)
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{
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if(MTIMINGR_HDEBUG) fprintf(stderr, "correction_offset = %d, reset to 0!\n", correction_offset);
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correction_offset = 0;
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}
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output[si++] = input[current_bitstart_index];
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error = (
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iof(input, current_bitstart_index + num_samples_quarterbit * 3) - iof(input, current_bitstart_index + num_samples_quarterbit)
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) * iof(input, current_bitstart_index + num_samples_halfbit);
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int el_point_left_index = current_bitstart_index + num_samples_quarterbit * 3;
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int el_point_right_index = current_bitstart_index + num_samples_quarterbit * 1 - correction_offset;
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int el_point_mid_index = current_bitstart_index + num_samples_halfbit;
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error = ( iof(input, el_point_left_index) - iof(input, el_point_right_index)) * iof(input, el_point_mid_index);
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if(state->use_q)
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{
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error += (
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qof(input, current_bitstart_index + num_samples_quarterbit * 3) - qof(input, current_bitstart_index + num_samples_quarterbit)
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) * qof(input, current_bitstart_index + num_samples_halfbit);
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error += ( qof(input, el_point_left_index) - qof(input, el_point_right_index)) * qof(input, el_point_mid_index);
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error /= 2;
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}
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//Correction method #1: this version can only move a single sample in any direction
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//current_bitstart_index += num_samples_halfbit * 2 + (error)?((error<0)?1:-1):0;
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//current_bitstart_index += num_samples_halfbit * 2 + (error)?((error<0)?1:-1):0;
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//Correction method #2: this can move in proportional to the error
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if(error>2) error=2;
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if(error<-2) error=-2;
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if(error>2) error=2;
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if(error<-2) error=-2;
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if( state->debug_force || (state->debug_phase >= si && debug_i) )
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{
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debug_i--;
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@ -1790,24 +1799,27 @@ void timing_recovery_cc(complexf* input, complexf* output, int input_size, timin
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octave_plot_point_on_cplxsig(input+current_bitstart_index, state->decimation_rate*2,
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error,
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current_bitstart_index,
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correction_offset,
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state->debug_writefiles,
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3,
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4,
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0 , 'b',
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num_samples_quarterbit * 1, 'r',
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num_samples_quarterbit * 2, 'r',
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num_samples_quarterbit * 3, 'r',
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0 , 'b',
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0);
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}
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current_bitstart_index += num_samples_bit + num_samples_halfbit * (-error/2);
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correction_offset = num_samples_halfbit * (-error/2);
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current_bitstart_index += num_samples_bit + correction_offset;
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if(si>=input_size)
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{
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if(MTIMINGR_HDEBUG) fprintf(stderr, "oops_out_of_si!\n");
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break;
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}
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}
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state->input_processed = current_bitstart_index;
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state->output_size = si;
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}
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state->input_processed = current_bitstart_index;
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state->output_size = si;
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state->last_correction_offset = correction_offset;
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}
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#define MTIMINGR_GAS(NAME) \
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@ -307,6 +307,7 @@ typedef struct timing_recovery_state_s
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int debug_count;
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int debug_force;
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int debug_writefiles;
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int last_correction_offset;
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} timing_recovery_state_t;
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timing_recovery_state_t timing_recovery_init(timing_recovery_algorithm_t algorithm, int decimation_rate, int use_q);
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@ -314,4 +315,4 @@ void timing_recovery_cc(complexf* input, complexf* output, int input_length, tim
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timing_recovery_algorithm_t timing_recovery_get_algorithm_from_string(char* input);
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char* timing_recovery_get_string_from_algorithm(timing_recovery_algorithm_t algorithm);
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void timing_recovery_trigger_debug(timing_recovery_state_t* state, int debug_phase);
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void octave_plot_point_on_cplxsig(complexf* signal, int signal_size, float error, int index, int writefiles, int points_size, ...);
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void octave_plot_point_on_cplxsig(complexf* signal, int signal_size, float error, int index, int correction_offset, int writefiles, int points_size, ...);
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