--- a/autocal/Makefile	Mon May 22 21:19:33 2017 +0000
+++ b/autocal/Makefile	Mon May 22 22:00:36 2017 +0000
@@ -2,7 +2,7 @@
 CFLAGS=	-O2 -I/opt/freecalypso/include
 PROGS=	fc-rfcal-vcxo
 
-VCXO_OBJS=	l1tmops.o rvinterf.o sockopts.o tsidsock.o vcxomain.o
+VCXO_OBJS=	l1tmops.o rvinterf.o sockopts.o tsidsock.o vcxomain.o vcxomeas.o
 
 all:	${PROGS}
 

--- a/autocal/vcxomain.c	Mon May 22 21:19:33 2017 +0000
+++ b/autocal/vcxomain.c	Mon May 22 22:00:36 2017 +0000
@@ -12,6 +12,12 @@
 #define	VCXOCAL_BAND_RFPW	RFPW_STD_BAND(6, 0)
 #define	VCXOCAL_ARFCN		40
 
+extern float vcxo_freq_meas();
+
+static float freq_max_neg, freq_max_pos;
+static float lin_a, lin_b, lin_a2, lin_b2;
+static int center_search_start;
+
 prepare_rf_test_system()
 {
 	char cmd[80];
@@ -39,5 +45,18 @@
 	printf("Starting RF Tx on the DUT\n");
 	do_rfe(RX_TX_TCH);
 
+	/* initial measurements at the DAC extremes */
+	freq_max_neg = vcxo_freq_meas(-2048, "max-neg");
+	freq_max_pos = vcxo_freq_meas(2048, "max-pos");
+	lin_a = (freq_max_pos - freq_max_neg) / 4096.0f;
+	lin_b = freq_max_pos - lin_a * 2048.0f;
+	center_search_start = -lin_b / lin_a;
+	printf("Center search start DAC value: %d\n", center_search_start);
+	vcxo_freq_meas(center_search_start, "center");
+	vcxo_freq_meas(center_search_start - 100, "center-delta");
+	vcxo_freq_meas(center_search_start + 100, "center+delta");
 
+	printf("Stopping RF Tx on the DUT\n");
+	do_rfe(STOP_ALL);
+	exit(0);
 }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/autocal/vcxomeas.c	Mon May 22 22:00:36 2017 +0000
@@ -0,0 +1,29 @@
+/*
+ * This module contains the frequency measurement code for fc-rfcal-vcxo.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <rvinterf/l1tm.h>
+#include <rvinterf/exitcodes.h>
+
+extern char tsid_response[];
+
+float
+vcxo_freq_meas(dac, hint)
+	int dac;
+	char *hint;
+{
+	char cmd[80];
+	double meas;
+
+	printf("Performing frequency measurement at DAC=%d (%s)\n", dac, hint);
+	do_rfpw(AFC_DAC_VALUE, dac);
+	usleep(80000);
+	sprintf(cmd, "freq-meas %s\n", hint);
+	tsid_command(cmd);
+	atof(tsid_response + 1);
+	printf("Measured frequency offset %.2f Hz\n", meas);
+	return(meas);
+}