diff --git a/README.md b/README.md
index 90445c3..576e757 100755
--- a/README.md
+++ b/README.md
@@ -828,6 +828,23 @@ For this input, the output of `psk31_varicode_encoder_u8_u8` will be the followi
 
 ----
 
+### [repeat_u8](#repeat_u8)
+
+Syntax:
+
+	repeat_u8 <taps_length> [resonator_rate × N]\n"
+
+It repeatedly outputs a set of data bytes (given with decimal numbers).
+
+For example, `csdr repeat_u8 1 1 0 0` will output:
+
+```
+01 01 00 00 01 01 00 00 
+01 01 00 00 01 01 00 00
+```
+
+----
+
 ### [?](#search_the_function_list)
 
 Syntax: 
diff --git a/csdr.c b/csdr.c
index 1283254..4e3aec8 100755
--- a/csdr.c
+++ b/csdr.c
@@ -139,6 +139,7 @@ char usage[]=
 "    simple_agc_cc <rate> [reference [max_gain]]\n"
 "    firdes_resonator_c <rate> <length> [window [--octave]]\n"
 "    resonators_fir_cc <taps_length> [resonator_rate × N]\n"
+"    repeat_u8 <data_bytes × N>\n"
 "    ?<search_the_function_list>\n"
 "    =<evaluate_python_expression>\n"
 "    \n"
@@ -2516,7 +2517,7 @@ int main(int argc, char *argv[])
 		}
 	}
 
-	if(!strcmp(argv[1],"timing_recovery_cc")) //<algorithm> <decimation> [--add_q [--octave <debug_n>]] 
+	if(!strcmp(argv[1],"timing_recovery_cc")) //<algorithm> <decimation> [--add_q [--output_error | --octave <debug_n>]] 
 	{
 		if(argc<=2) return badsyntax("need required parameter (algorithm)");
 		timing_recovery_algorithm_t algorithm = timing_recovery_get_algorithm_from_string(argv[2]);
@@ -2530,8 +2531,12 @@ int main(int argc, char *argv[])
 		int add_q = (argc>=5 && !strcmp(argv[4], "--add_q"));
 
 		int debug_n = 0;
+        int output_error = 0;
 		if(argc>=7 && !strcmp(argv[5], "--octave")) debug_n = atoi(argv[6]);
 		if(debug_n<0) badsyntax("debug_n should be >= 0");
+        if(argc>=6 && !strcmp(argv[5], "--output_error")) output_error = 1;
+        float* timing_error = NULL;
+        if(output_error) timing_error = (float*)malloc(sizeof(float)*the_bufsize);
 
 		if(!initialize_buffers()) return -2;
 		sendbufsize(the_bufsize/decimation);
@@ -2546,9 +2551,10 @@ int main(int argc, char *argv[])
 		{
 			FEOF_CHECK;
 			if(debug_n && ++debug_i%debug_n==0) timing_recovery_trigger_debug(&state, 3);
-			timing_recovery_cc((complexf*)input_buffer, (complexf*)output_buffer, the_bufsize, &state);
+			timing_recovery_cc((complexf*)input_buffer, (complexf*)output_buffer, the_bufsize, timing_error, &state);
 			//fprintf(stderr, "trcc is=%d, os=%d, ip=%d\n",the_bufsize, state.output_size, state.input_processed);
-			fwrite(output_buffer, sizeof(complexf), state.output_size, stdout);
+			if(timing_error) fwrite(timing_error, sizeof(float), state.output_size, stdout);
+            else fwrite(output_buffer, sizeof(complexf), state.output_size, stdout);
 			TRY_YIELD;
 			//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
@@ -2867,6 +2873,19 @@ int main(int argc, char *argv[])
 		}
 	}
 
+    if(!strcmp(argv[1], "repeat_u8"))
+    {
+        if(argc<=2) badsyntax("no data to repeat");
+        unsigned char* repeat_buffer = (unsigned char*)malloc(sizeof(unsigned char)*(argc-2));
+        for(int i=0;i<argc-2;i++)
+        {
+            int current_val;
+            sscanf(argv[i+2], "%d", &current_val); 
+            repeat_buffer[i]=current_val;
+        }
+        for(;;) fwrite(repeat_buffer, sizeof(unsigned char), argc-2, stdout);
+    }
+
 	if(!strcmp(argv[1],"none"))
 	{
 		return 0;
diff --git a/grc_tests/bpsk31_baseband_sample_complex_8000_sps_010101.raw b/grc_tests/bpsk31_baseband_sample_complex_8000_sps_010101.raw
new file mode 100644
index 0000000..91b4ab1
Binary files /dev/null and b/grc_tests/bpsk31_baseband_sample_complex_8000_sps_010101.raw differ
diff --git a/grc_tests/bpsk31_scurve.m b/grc_tests/bpsk31_scurve.m
new file mode 100755
index 0000000..5e0b3a8
--- /dev/null
+++ b/grc_tests/bpsk31_scurve.m
@@ -0,0 +1,38 @@
+#!/usr/bin/octave
+
+%{
+function [output]=fgc(path, type)
+	if(type(1)=='f')
+	elseif(type(1)=='c')
+	end
+end
+%}
+
+function output=shrunf(cmd)
+	SIGTERM=15;
+	output=[];
+	[pin, pout, pid]=popen2('bash',{'-c', cmd});
+	%fclose(pin);
+	sleep(0.1)
+	do
+		current_output=fread(pout, Inf, 'float32');
+		output=[output; current_output];
+	until(feof(pout))
+	waitpid(pid);
+	%kill(pid, SIGTERM);
+end
+
+function error_value=run_tr(skip)
+	out_vect=shrunf(sprintf('dd bs=8 skip=%d if=grc_tests/bpsk31_baseband_sample_complex_8000_sps_010101.raw | csdr timing_recovery_cc EARLYLATE 256 --add_q --output_error',skip));
+	error_value=out_vect(2);
+end
+
+skips=0:400
+error_values=[]
+for skip=skips
+	error_values=[error_values run_tr(skip)];
+end
+
+error_values
+plot(skips, error_values);
+pause
diff --git a/libcsdr.c b/libcsdr.c
index e0a6851..2901331 100755
--- a/libcsdr.c
+++ b/libcsdr.c
@@ -1919,7 +1919,7 @@ void timing_recovery_trigger_debug(timing_recovery_state_t* state, int debug_pha
 
 #define MTIMINGR_HDEBUG 0
 
-void timing_recovery_cc(complexf* input, complexf* output, int input_size, timing_recovery_state_t* state)
+void timing_recovery_cc(complexf* input, complexf* output, int input_size, float* timing_error, timing_recovery_state_t* state)
 {
 	//We always assume that the input starts at center of the first symbol cross before the first symbol.
 	//Last time we consumed that much from the input samples that it is there.
@@ -1977,6 +1977,8 @@ void timing_recovery_cc(complexf* input, complexf* output, int input_size, timin
 			}
 			//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;
+
+            if(timing_error) timing_error[si-1]=error; //it is not written if NULL
 			
 			if(error>2) error=2;
 			if(error<-2) error=-2;
diff --git a/libcsdr.h b/libcsdr.h
index 0a0febf..8617282 100644
--- a/libcsdr.h
+++ b/libcsdr.h
@@ -334,7 +334,7 @@ typedef struct timing_recovery_state_s
 } timing_recovery_state_t;
 
 timing_recovery_state_t timing_recovery_init(timing_recovery_algorithm_t algorithm, int decimation_rate, int use_q);
-void timing_recovery_cc(complexf* input, complexf* output, int input_length, timing_recovery_state_t* state);
+void timing_recovery_cc(complexf* input, complexf* output, int input_size, float* timing_error, timing_recovery_state_t* state);
 timing_recovery_algorithm_t timing_recovery_get_algorithm_from_string(char* input);
 char* timing_recovery_get_string_from_algorithm(timing_recovery_algorithm_t algorithm);
 void timing_recovery_trigger_debug(timing_recovery_state_t* state, int debug_phase);