Added FM modulator.

csdr.c

@@ -1562,6 +1562,20 @@ int main(int argc, char *argv[])
 		}		
 	}
 
+	if(!strcmp(argv[1],"fmmod_fc"))
+	{
+		if(!sendbufsize(initialize_buffers())) return -2;
+		float last_phase = 0;
+		for(;;)
+		{
+			FEOF_CHECK;
+			FREAD_R;
+			last_phase = fmmod_fc(input_buffer, (complexf*)output_buffer, the_bufsize, last_phase);
+			FWRITE_C;
+			TRY_YIELD;
+		}		
+	}
+
 	if(!strcmp(argv[1],"none"))
 	{
 		return 0;

libcsdr.c

@@ -834,6 +834,20 @@ void add_dcoffset_cc(complexf* input, complexf* output, int input_size)
 	for(int i=0;i<input_size;i++) qof(output,i)=qof(input,i)/2; 
 }
 
+float fmmod_fc(float* input, complexf* output, int input_size, float last_phase)
+{
+	float phase=last_phase;
+	for(int i=0;i<input_size;i++)
+	{
+		phase+=input[i]*PI;
+		while(phase>PI) phase-=2*PI;
+		while(phase<=-PI) phase+=2*PI;
+		iof(output,i)=cos(phase);
+		qof(output,i)=sin(phase);
+	}
+	return phase;
+}
+
 /*
   ______        _     ______               _             _______                   __                     
  |  ____|      | |   |  ____|             (_)           |__   __|                 / _|                    

libcsdr.h

@@ -163,6 +163,7 @@ void apply_fir_fft_cc(FFT_PLAN_T* plan, FFT_PLAN_T* plan_inverse, complexf* taps
 void gain_ff(float* input, float* output, int input_size, float gain);
 
 void add_dcoffset_cc(complexf* input, complexf* output, int input_size);
+float fmmod_fc(float* input, complexf* output, int input_size, float last_phase);
 
 void convert_u8_f(unsigned char* input, float* output, int input_size);
 void convert_f_u8(float* input, unsigned char* output, int input_size);