Added a squelch

README.md

@@ -387,6 +387,10 @@ It doubles every input sample.
 
 See the [buffer sizes](#buffer_sizes) section.
 
+	squelch_and_smeter_cc --fifo <squelch_fifo> --outfifo <smeter_fifo> <use_every_nth> <report_every_nth>
+
+This is a controllable squelch, which reads the squelch level input from `<squelch_fifo>` and writes the power level output to `<smeter_fifo>`. Both input and output are in the format of `%g\n`. While calculating the power level, it takes only every `<use_every_nth>` sample into consideration. It writes the S-meter value for every `<report_every_nth>` buffer to `<smeter_fifo>`. If the squelch level is set to 0, it it forces the squelch to be open. If the squelch is closed, it fills the output with zero.
+
 #### Control via pipes
 
 Some parameters can be changed while the `csdr` process is running. To achieve this, some `csdr` functions have special parameters. You have to supply a fifo previously created by the `mkfifo` command. Processing will only start after the first control command has been received by `csdr` over the FIFO.

csdr.c

@@ -71,7 +71,9 @@ char usage[]=
 "    floatdump_f\n"
 "    flowcontrol <data_rate> <reads_per_second> [prebuffer_sec] [thrust]\n"
 "    shift_math_cc <rate>\n"
+"    shift_math_cc --fifo <fifo_path>\n"
 "    shift_addition_cc <rate>\n"
+"    shift_addition_cc --fifo <fifo_path>\n"
 "    shift_addition_cc_test\n"
 "    shift_table_cc <rate> [table_size]\n"
 "    decimating_shift_addition_cc <rate> [decimation]\n"
@@ -95,6 +97,7 @@ char usage[]=
 "    logpower_cf [add_db]\n"
 "    fft_benchmark <fft_size> <fft_cycles> [--benchmark]\n"
 "    bandpass_fir_fft_cc <low_cut> <high_cut> <transition_bw> [window]\n"
+"    bandpass_fir_fft_cc --fifo <fifo_path> <transition_bw> [window]\n"
 "    encode_ima_adpcm_s16_u8\n"
 "    decode_ima_adpcm_u8_s16\n"
 "    compress_fft_adpcm_f_u8 <fft_size>\n"
@@ -107,6 +110,7 @@ char usage[]=
 "    monos2stereo_s16\n"
 "    setbuf <buffer_size>\n"
 "    fft_exchange_sides_ff <fft_size>\n"
+"    squelch_and_smeter_cc --fifo <squelch_fifo> --outfifo <smeter_fifo> <use_every_nth> <report_every_nth>\n"
 "    \n"
 ;
 
@@ -1681,6 +1685,59 @@ int main(int argc, char *argv[])
 		}
 	}
 
+	if(!strcmp(argv[1],"squelch_and_smeter_cc"))
+	{
+		if(!sendbufsize(initialize_buffers())) return -2;
+		float power;
+		float squelch_level;
+		int decimation;
+		int report_every_nth;
+		int fd;
+		char power_value_buf[101];
+		int power_value_buf_size;
+		int report_cntr=0;
+		complexf* zerobuf = (complexf*)malloc(sizeof(complexf)*the_bufsize);
+		for(int i=0;i<the_bufsize*2;i++) *(((float*)zerobuf)+i)=0;
+		if(fd=init_fifo(argc,argv)) while(!read_fifo_ctl(fd,"%g\n",&squelch_level)) usleep(10000);
+		else return badsyntax("need required parameter (--fifo <fifo>)");
+		fprintf(stderr, "squelch_and_power_cc: initial squelch level is %g\n", squelch_level);
+		if((argc<=5)||((argc>5)&&(strcmp(argv[4],"--outfifo")))) return badsyntax("need required parameter (--outfifo <fifo>)");
+		int fd2 = open(argv[5], O_WRONLY);
+		if(fd2==-1) return badsyntax("error while opening --outfifo");
+		int flags = fcntl(fd2, F_GETFL, 0);
+		fcntl(fd2, F_SETFL, flags | O_NONBLOCK);
+		if(argc<=6) return badsyntax("need required parameter (use_every_nth)");
+		sscanf(argv[6],"%d",&decimation);
+		if(decimation<=0) return badsyntax("use_every_nth <= 0 is invalid");
+		if(argc<=7) return badsyntax("need required parameter (report_every_nth)");
+		sscanf(argv[7],"%d",&report_every_nth);
+		if(report_every_nth<=0) return badsyntax("report_every_nth <= 0 is invalid");
+		for(;;)
+		{
+			FEOF_CHECK;
+			FREAD_C; //read input data
+			power = get_power_c((complexf*)input_buffer, the_bufsize, decimation);
+			if(report_cntr++>report_every_nth)
+			{
+				report_cntr=0;
+				power_value_buf_size=snprintf(power_value_buf,100,"%g\n",power);
+				write(fd2,power_value_buf,power_value_buf_size*sizeof(char));
+		  }
+			if(squelch_level==0||power>=squelch_level)
+			{
+				//fprintf(stderr,"P");
+				fwrite(input_buffer, sizeof(complexf), the_bufsize, stdout);
+			}
+			else
+			{
+				//fprintf(stderr,"S");
+				fwrite(zerobuf, sizeof(complexf), the_bufsize, stdout);
+			}
+			if(read_fifo_ctl(fd,"%g\n",&squelch_level)) fprintf(stderr, "squelch_and_power_cc: new squelch level is %g\n", squelch_level);
+			TRY_YIELD;
+		}
+	}
+
 	if(!strcmp(argv[1],"none"))
 	{
 		return 0;
@@ -1689,5 +1746,3 @@ int main(int argc, char *argv[])
 	return badsyntax("function name given in argument 1 does not exist. Possible causes:\n- You mistyped the commandline.\n- You need to update csdr to a newer version (if available).");
 
 }
-
-

libcsdr.c

@@ -818,6 +818,26 @@ void gain_ff(float* input, float* output, int input_size, float gain)
 	for(int i=0;i<input_size;i++) output[i]=gain*input[i]; //@gain_ff
 }
 
+float get_power_f(float* input, int input_size, int decimation)
+{
+  float acc = 0;
+  for(int i=0;i<input_size;i+=decimation)
+  {
+    acc += (input[i]*input[i])/input_size;
+  }
+  return acc;
+}
+
+float get_power_c(complexf* input, int input_size, int decimation)
+{
+  float acc = 0;
+  for(int i=0;i<input_size;i+=decimation)
+  {
+    acc += (iof(input,i)*iof(input,i)+qof(input,i)*qof(input,i))/input_size;
+  }
+  return acc;
+}
+
 /*
   __  __           _       _       _
  |  \/  |         | |     | |     | |
@@ -989,5 +1009,3 @@ int trivial_vectorize()
 	}
 	return c[0];
 }
-
-

libcsdr.h

@@ -161,6 +161,8 @@ int log2n(int x);
 int next_pow2(int x);
 void apply_fir_fft_cc(FFT_PLAN_T* plan, FFT_PLAN_T* plan_inverse, complexf* taps_fft, complexf* last_overlap, int overlap_size);
 void gain_ff(float* input, float* output, int input_size, float gain);
+float get_power_f(float* input, int input_size, int decimation);
+float get_power_c(complexf* input, int input_size, int decimation);
 
 void add_dcoffset_cc(complexf* input, complexf* output, int input_size);
 float fmmod_fc(float* input, complexf* output, int input_size, float last_phase);