bpsk_costas_loop_cc function added to csdr

csdr.c

@@ -131,6 +131,7 @@ char usage[]=
 "    psk_modulator_u8_c <n_psk>\n"
 "    psk31_interpolate_sine_cc\n"
 "    duplicate_samples_ntimes_u8_u8 <sample_size_bytes> <ntimes>\n"
+"    bpsk_costas_loop_cc <samples_per_bits>\n"
 "    ?<search_the_function_list>\n"
 "    \n"
 ;
@@ -2396,7 +2397,7 @@ int main(int argc, char *argv[])
 			fwrite(output_buffer, sizeof(complexf), state.output_size, stdout);
 			fflush(stdout);
 			TRY_YIELD;
-			fprintf(stderr, "state.input_processed = %d\n", state.input_processed);
+			//fprintf(stderr, "state.input_processed = %d\n", state.input_processed);
 			memmove((complexf*)input_buffer,((complexf*)input_buffer)+state.input_processed,(the_bufsize-state.input_processed)*sizeof(complexf)); //memmove lets the source and destination overlap
 			fread(((complexf*)input_buffer)+(the_bufsize-state.input_processed), sizeof(complexf), state.input_processed, stdin);
 			//fprintf(stderr,"iskip=%d state.output_size=%d start=%x target=%x skipcount=%x \n",state.input_processed,state.output_size,input_buffer, ((complexf*)input_buffer)+(BIG_BUFSIZE-state.input_processed),(BIG_BUFSIZE-state.input_processed));
@@ -2575,6 +2576,28 @@ int main(int argc, char *argv[])
 		}
 	}
 
+	if(!strcmp(argv[1],"bpsk_costas_loop_cc")) //<samples_per_bits>
+	{
+		float samples_per_bits;
+		if(argc<=2) return badsyntax("need required parameter (samples_per_bits)");
+		sscanf(argv[2],"%f",&samples_per_bits);
+		if(samples_per_bits<=0) badsyntax("samples_per_bits should be >= 0");
+
+		bpsk_costas_loop_state_t state = init_bpsk_costas_loop_cc(samples_per_bits);
+
+		if(!initialize_buffers()) return -2;
+		sendbufsize(the_bufsize);
+
+		for(;;)
+		{
+			FEOF_CHECK;
+			FREAD_C;
+			bpsk_costas_loop_cc((complexf*)input_buffer, (complexf*)output_buffer, the_bufsize, &state);
+			FWRITE_C;
+			TRY_YIELD;
+		}
+	}
+
 	if(!strcmp(argv[1],"none"))
 	{
 		return 0;

libcsdr.c

@@ -1907,34 +1907,35 @@ char* timing_recovery_get_string_from_algorithm(timing_recovery_algorithm_t algo
 	return "INVALID";
 }
 
-typedef struct bpsk_costas_loop_state_s
-{
-	float rc_filter_alpha;
-	float vco_phase_addition_multiplier;
-	float vco_phase;
-	float last_lpfi_output;
-	float last_lpfq_output;
-} bpsk_costas_loop_state_t;
-
-void init_bpsk_costas_loop_cc(bpsk_costas_loop_state_t* state, float samples_per_bits) 
+bpsk_costas_loop_state_t init_bpsk_costas_loop_cc(float samples_per_bits) 
 { 
-	state->vco_phase = 0;
+	bpsk_costas_loop_state_t state;
+	state.vco_phase = 0;
 	float virtual_sampling_rate = 10000;
 	float virtual_data_rate = virtual_sampling_rate / samples_per_bits;
+	fprintf(stderr, "virtual_sampling_rate = %g, virtual_data_rate = %g\n", virtual_sampling_rate, virtual_data_rate);
 	float rc_filter_cutoff = virtual_data_rate/2;
 	float rc_filter_rc = 1/(2*M_PI*rc_filter_cutoff); //as of Equation 24 in Feigin
 	float virtual_sampling_dt = 1.0/virtual_sampling_rate;
-	state->rc_filter_alpha = virtual_sampling_dt/(rc_filter_rc+virtual_sampling_dt); //https://en.wikipedia.org/wiki/Low-pass_filter
+	fprintf(stderr, "rc_filter_cutoff = %g, rc_filter_rc = %g, virtual_sampling_dt = %g\n", 
+		rc_filter_cutoff, rc_filter_rc, virtual_sampling_dt);
+	state.rc_filter_alpha = virtual_sampling_dt/(rc_filter_rc+virtual_sampling_dt); //https://en.wikipedia.org/wiki/Low-pass_filter
 	float rc_filter_omega_cutoff = 2*M_PI*rc_filter_cutoff;
-	state->vco_phase_addition_multiplier = 8*rc_filter_omega_cutoff; //as of Equation 25 in Feigin, assuming input signal amplitude of 1 (to 1V) and (state->vco_phase_addition_multiplier*<vco_input>), a value in radians, will be added to the vco_phase directly.
+	state.vco_phase_addition_multiplier = 8*rc_filter_omega_cutoff; //as of Equation 25 in Feigin, assuming input signal amplitude of 1 (to 1V) and (state.vco_phase_addition_multiplier*<vco_input>), a value in radians, will be added to the vco_phase directly.
+	fprintf(stderr, "rc_filter_alpha = %g, rc_filter_omega_cutoff = %g, vco_phase_addition_multiplier = %g\n", 
+			state.rc_filter_alpha, rc_filter_omega_cutoff, state.vco_phase_addition_multiplier);
+	return state;
 }
 
 void bpsk_costas_loop_cc(complexf* input, complexf* output, int input_size, bpsk_costas_loop_state_t* state)
 {
+	int debug = 0;
+	if(debug) fprintf(stderr, "costas:\n");
 	for(int i=0;i<input_size;i++)
 	{
 		float input_phase = atan2(input[i].q, input[i].i);
 		float input_and_vco_mixed_phase = input_phase - state->vco_phase;
+		if(debug) fprintf(stderr, "%g | %g\n", input_and_vco_mixed_phase, input_phase), debug--;
 		complexf input_and_vco_mixed_sample; 
 		e_powj(&input_and_vco_mixed_sample, input_and_vco_mixed_phase);
 		float loop_output_i = 
@@ -1947,6 +1948,8 @@ void bpsk_costas_loop_cc(complexf* input, complexf* output, int input_size, bpsk
 		state->vco_phase += vco_phase_addition;
 		while(state->vco_phase>PI) state->vco_phase-=2*PI;
 		while(state->vco_phase<-PI) state->vco_phase+=2*PI;
+		output[i].i = loop_output_i;
+		output[i].q = loop_output_q;
 	}
 }
 

libcsdr.h

@@ -323,3 +323,15 @@ complexf psk31_interpolate_sine_cc(complexf* input, complexf* output, int input_
 void pack_bits_8to1_u8_u8(unsigned char* input, unsigned char* output, int input_size);
 void psk31_varicode_encoder_u8_u8(unsigned char* input, unsigned char* output, int input_size, int output_max_size, int* input_processed, int* output_size);
 unsigned char differential_codec(unsigned char* input, unsigned char* output, int input_size, int encode, unsigned char state);
+
+typedef struct bpsk_costas_loop_state_s
+{
+	float rc_filter_alpha;
+	float vco_phase_addition_multiplier;
+	float vco_phase;
+	float last_lpfi_output;
+	float last_lpfq_output;
+} bpsk_costas_loop_state_t;
+
+bpsk_costas_loop_state_t init_bpsk_costas_loop_cc(float samples_per_bits);
+void bpsk_costas_loop_cc(complexf* input, complexf* output, int input_size, bpsk_costas_loop_state_t* state);