#include <tcpsupp.h>
#include <utility.h>
#include <ansi_c.h>
#include <lowlvlio.h>
#include <cvirte.h>		
#include <userint.h>
#include <formatio.h>
#include <inifile.h>
#include <string.h>

#include "FXAnalyse.h" 
#include "Plot.h"
#include "Allan.h"
#include "ad9912.h"
#include "ad9956.h" 
#include "muParserDLL.h"
#include "utils.h"
#include "stat.h"
#include "future.h"
#include "data-provider.h"
#include "sr-data-logger.h"
#include "config.h"
#include "logging.h"


#define FREP_STEP_SIZE 50000.0

#define SPEED_OF_LIGHT 299792458.0 // m/s

#define SR_FREQUENCY   429.228293 // THz
#define SR_WAVELENGTH  (SPEED_OF_LIGHT / SR_FREQUENCY / 1.0e3) // nm

#define HG_FREQUENCY   282.143622 // THz
#define HG_WAVELENGTH  (SPEED_OF_LIGHT / HG_FREQUENCY / 1.0e3) // nm


// select which data provider to use
#ifdef NDEBUG
#define DataProvider KKDataProvider
#else
#define DataProvider FakeDataProvider
#endif


// data acquisition status
int acquiring;
// data queue
CmtTSQHandle dataQueue;
// data provider thread
CmtThreadFunctionID dataProviderThread;


struct event event;
double utc;
double Ch1, Ch2, Ch3, Ch4;
double Math1, Math2, Math3, Math4, Math5;
double N1, N2, N3;
double Ndiv = 8.0;
double Sign1 = 1, Sign2 = 1, Sign3 = 1;
void *MathParser1, *MathParser2, *MathParser3, *MathParser4, *MathParser5;


// panels
static int MainPanel;
static int CalcNPanel;
static int EstimateNPanel;


struct adev {
	Allan_Data allan;
	double *data;
	const char *title;
	double normalization;
	int control;
};


#define ADEV(__channel, __normalization)		\
	{											\
		.data = & ## __channel,					\
		.title = "Adev " #__channel,		    \
		.normalization = __normalization,		\
		.control = PANEL_ADEV_ ## __channel		\
	}


static int adev_toggle(struct adev *adev)
{
	if (adev->allan.active)
		Allan_ClosePanel(&(adev->allan));
	else
		Allan_InitPanel(&(adev->allan), adev->title,
			adev->normalization, MainPanel, adev->control);
	return adev->allan.active;
}


static inline void adev_update(struct adev *adev)
{
	if (adev->allan.active)
		Allan_AddFrequency(&(adev->allan), *(adev->data));
}


struct adev adevs[] = {
	ADEV(Ch1, 1.84e12),
	ADEV(Ch2, 10.0e3),
	ADEV(Ch3, 429.228e12),
	ADEV(Ch4, 275.0e3),
	ADEV(Math1, 250.0e6),
	ADEV(Math2, 194.395e12),
	ADEV(Math3, 282.143e12),
	ADEV(Math4, 429.228e12),
	ADEV(Math5, 1.0),
	{ NULL }
};


struct plot {
	Plot_Data plot;
	double *data;
	const char *title;
	double min;
	double max;
	int control;
};


#define PLOT(__channel, __min, __max) 			\
	{											\
		.data = & ## __channel, 				\
		.title = "Plot " #__channel,			\
		.min = __min,							\
		.max = __max,							\
		.control = PANEL_PLOT_ ## __channel		\
	}


static int plot_toggle(struct plot *plot)
{
	if (plot->plot.active)
		Plot_ClosePanel(&(plot->plot));
	else
		Plot_InitPanel(&(plot->plot), plot->title,
			plot->min, plot->max, MainPanel, plot->control);
	return plot->plot.active;
}


static inline void plot_update(struct plot *plot)
{
	if (plot->plot.active)
		Plot_AddFrequency(&(plot->plot), *(plot->data));
}

struct plot plots[] = {
	PLOT(Ch1, 54.999e6, 55.001e6),
	PLOT(Ch2, 0.0, 0.0),
	PLOT(Ch3, 0.0, 0.0),
	PLOT(Ch4, 0.0, 0.0),
	PLOT(Math1, 0.0, 0.0),
	PLOT(Math2, 0.0, 0.0),
	PLOT(Math3, 0.0, 0.0),
	PLOT(Math4, 0.0, 0.0),
	PLOT(Math5, 0.0, 0.0),
	{ NULL }
};


struct ad9956 ad9956;
struct ad9912 ad9912;


static inline int ad9912_set_frequency_w(struct ad9912 *d, unsigned c, double f)
{
	int r = ad9912_set_frequency(d, c, f);
	if (r)
		logmessage(ERROR, "ad9912 set frequency channel=%d error=%d", c, -r);
	return r;
}


static inline int ad9912_ramp_frequency_w(struct ad9912 *d, unsigned c, double f, double s)
{
	int r = ad9912_ramp_frequency(d, c, f, s);
	if (r)
		logmessage(ERROR, "ad9912 ramp frequency channel=%d error=%d", c, -r);
	return r;
}


static inline int ad9956_set_sweep_rate_w(struct ad9956 *d, double s)
{
	int r = ad9956_set_sweep_rate(d, s);
	if (r)
		logmessage(ERROR, "ad9956 set sweep rate error=%d", -r);
	return r;
}


static int ad9956_set_w(struct ad9956 *d, double f, double s)
{
	int r;
	
	r = ad9956_sweep_stop(d);
	if (r) {
		logmessage(ERROR, "ad9956 sweep stop error=%d", -r);
		return r;
	}
	
	r = ad9956_set_frequency(d, f);
	if (r) {
		logmessage(ERROR, "ad9956 set frequency error=%d", -r);
		return r;
	}
	
	r = ad9956_set_sweep_rate(d, s);
	if (r) {
		logmessage(ERROR, "ad9956 set sweep rate error=%d", -r);
		return r;
	}
	
	r = ad9956_sweep_start(d);
	if (r) {
		logmessage(ERROR, "ad9956 sweep start error=%d", -r);
		return r;
	}

	return 0;	
}


enum {
	LO = 1,
	HG = 2,
	SR = 4,
};

enum {
	N_MEASUREMENT_NONE,
	N_MEASUREMENT_INIT,
	N_MEASUREMENT_SLOPE,
	N_MEASUREMENT_ADJUST_FREQ_PLUS,
	N_MEASUREMENT_FREP_PLUS,
	N_MEASUREMENT_ADJUST_FREQ_MINUS,
	N_MEASUREMENT_FREP_MINUS,
};

int n_measurement_1 = N_MEASUREMENT_NONE;
int n_measurement_2 = N_MEASUREMENT_NONE;
int n_measurement_3 = N_MEASUREMENT_NONE;

int nobs = 0;
int settling = 0;

double f0_DDS1 = 110000000.0, f0_DDS2, f0_DDS3, f0_DDS4, df_DDS3;

double slope_time_1 = 40.0, integration_time_1 = 40.0, delta_f_lock_1 = 500e3;
double slope_time_2 = 40.0, integration_time_2 = 40.0, delta_f_lock_2 = 500e3;
double slope_time_3 = 40.0, integration_time_3 = 40.0, delta_f_lock_3 = 500e3;

double t1, t2, t3;
double f_rep_slope, f_beat_slope;
double f_rep_plus, f_rep_minus;
double f_beat_plus, f_beat_minus;


// Beatnote sign determination is done stepping the repetition rate by
// stepping the comb phase-lock offset frequency f_lock generated by
// DDS1.  A lock frequency step delta_f_lock determines a change in the
// repetition rate given by:
//
//   abs(delta_f_rep) = Ndiv * delta_f_lock / N1
// 
// where Ndiv = 8 and N1 ~= 8 x 10^5 obtaining that
// 
//   abs(delta_f_rep) ~= delta_f_lock / 10^5
//
// For the determination of the comb locking beatnote sign we detect
// the sign of delta_f_rep caused by a positive delta_f_lock. f_rep is
// measured should be small enough to do not exceed the 200x PLL
// bandwidth but still be clearly identified.
// 
// For the optical beatnotes we detect the sign of delta_f_beat caused
// by a positive delta_f_lock thus we need to take into account the
// sign of the comb locking beatnote.  The optical beatnote frequency
// change is given by
// 
//   abs(delta_f_beat) = abs(delta_f_rep) * Nx
// 
// where Nx ~= 10^6 obtaining that
// 
//   abs(delta_f_beat) ~= delta_f_lock * 10
//
// this need to do not exceed the beatnote filters bandwidth.  Given
// those contraints the following f_lock steps are chosen:

double f_lock_step_1 = 10000.0;
double f_lock_step_2 = 10.0;
double f_lock_step_3 = 10.0;

struct beatsign {
	int measure;		// which beatnote sign is being measured
	double f0_DDS1;		// DDS1 frequency before stepping
	double t0;			// measurement start time
	double f_rep_zero;	// repetition rate before stepping
	double f_beat_zero;	// beatnote frequwncy before stepping
};

struct beatsign beatsign = {
	.measure = 0,
};


struct stat stat_math1, stat_ch2, stat_ch3;
struct rollmean rollmean_ch1, rollmean_ch2, rollmean_ch3, rollmean_ch4;


// dedrift
enum {
	DEDRIFT_REFERENCE_MICROWAVE = 0,
	DEDRIFT_REFERENCE_HG = 1,
};

struct dedrift {
	int enabled;        // dedrift enabled
	int proportional;   // enable proportional correction
	int reference;      // reference frequency
	int sign;           // sign of the correction
	int x2;    			// double the applied correction
	int keep_freq;      // keep current frequency value when dedrift is disabled
	int keep_slope;     // keep current slope value when dedrift is disabled
	double f0;          // target frequency
	double fDDS;        // DDS center frequency
	double threshold;   // maximum allowed frequency change
	double applied;     // currently applied slope
	double interval;    // measurement duration
	double t0;          // beginning of currrent measurement interval
	struct stat stat;   // frequency mean and slope
};

struct dedrift dedrift = {
	.enabled = FALSE,
	.proportional = FALSE,
	.reference = DEDRIFT_REFERENCE_MICROWAVE,
	.sign = +1,
	.x2 = FALSE,
	.keep_freq = TRUE,
	.keep_slope = TRUE,
	.f0 = 0.0,
	.fDDS = 70e6,
	.threshold = 100.0,
	.applied = 0.0,
	.interval = 30.0,
	.t0 = 0.0
};


void dedrift_update(double f)
{
	// stop dedrift if the comb is not locked
	if ((dedrift.enabled) &&
	    (dedrift.threshold != 0.0) &&
	    (dedrift.stat.previous != 0.0) &&
	    (fabs(f - dedrift.stat.previous) > dedrift.threshold)) {
		
		logmsg("dedrift stop: frequency jump detected");
					
		if (! dedrift.keep_slope) {
			dedrift.applied = 0.0;
			ad9956_set_sweep_rate_w(&ad9956, dedrift.applied);
			SetCtrlVal(MainPanel, PANEL_SLOPE_APPLIED, dedrift.applied);
		}
		if (! dedrift.keep_freq) {
			ad9956_set_w(&ad9956, dedrift.fDDS, dedrift.applied);
		}
		
		stat_zero(&dedrift.stat);
		SetCtrlVal(MainPanel, PANEL_SLOPE_MEASURED, dedrift.stat.slope);
		dedrift.enabled = FALSE;
		SetCtrlVal(MainPanel, PANEL_MEASURE_SLOPE, 0);
	}
	
	// dedrifting 
	if (dedrift.enabled) {

		// update measurement
		stat_accumulate(&dedrift.stat, f);
		SetCtrlVal(MainPanel, PANEL_SLOPE_MEASURED, dedrift.stat.slope);
		
		// update applied slope
		if ((utc - dedrift.t0) > dedrift.interval) {
			
			// target frequency
			if (dedrift.f0 == 0.0)
				dedrift.f0 = dedrift.stat.mean;

			// compute correction
			double dt = utc - dedrift.t0;
			double corr = dedrift.stat.slope \
				+ dedrift.proportional * ((dedrift.stat.mean - dedrift.f0) / dt + 0.5 * dedrift.stat.slope);

			// update
			dedrift.applied += dedrift.sign * corr * (dedrift.x2 ? 2 : 1);
			ad9956_set_sweep_rate_w(&ad9956, dedrift.applied);
			SetCtrlVal(MainPanel, PANEL_SLOPE_APPLIED, dedrift.applied);
			logmsg("dedrift update: correction=%+3e slope=%+3e", corr, dedrift.applied);

			// start over
			dedrift.t0 = utc;
			stat_zero(&dedrift.stat);
		}
	}
}


// recenter
struct recenter {
	int enabled;		// recenter enabled
	int lo;				// recenter microwave beatnote
	int sr;				// recenter Sr beatnote
	int hg;				// recenter Hg beatnote
	double interval;	// interval
	double t0;			// beginning of current interval
};

struct recenter recenter = {
	.enabled = FALSE,
	.lo = FALSE,
	.sr = FALSE,
	.hg = FALSE,
	.interval = 1800.0,
	.t0 = 0.0
};


// data loggging
static char *datafolder;

struct datafile {
	char *name;
	double *data;
	int nchan;
	int control;
	int write;
};

#define DATAFILE(__name, __data, __nchan, __control, __write)	\
	{															\
		.name = __name,											\
		.data = __data,											\
		.nchan = __nchan,										\
		.control = __control,									\
		.write = __write,										\
	}

struct datafile datafiles[] = {
     DATAFILE("Raw", event.data, 4, PANEL_SAVE_RAW, TRUE),
     DATAFILE("DDS", ad9912.frequency, 4, PANEL_SAVE_DDS, FALSE),
     DATAFILE("Lo", &Math2, 1, PANEL_SAVE_LO, FALSE),
     DATAFILE("Hg", &Math3, 1, PANEL_SAVE_HG, FALSE),
     DATAFILE("Sr", &Math4, 1, PANEL_SAVE_SR, FALSE),
     DATAFILE("Ex", &Math5, 1, PANEL_SAVE_EXTRA, FALSE),
     { NULL, }
};


static void write_data(const char *folder, const char *name, const char *id, 
		const char *timestr, double utc, double *v, int nchan)
{
	int i, fd, len;
	char line[1024];
	char filename[FILENAME_MAX];
	
	// construct filename in the form folder\\id-name.txt
	snprintf(filename, sizeof(filename), "%s\\%s-%s.txt", folder, id, name);
	
	fd = open(filename, O_CREAT|O_WRONLY|O_APPEND, 00744);
	if (fd < 0) {
		logmessage(ERROR, "open data file %s: %s", filename, strerror(errno));
		return;
	}
	
	// timestamp
	len = snprintf(line, sizeof(line), "%s\t%.3f", timestr, utc);

	// data channels
	for (i = 0; i < nchan; i++)
		len += snprintf(line + len, sizeof(line) - len, "\t%.16e", v[i]);
	
	// newline
	line[len++] = '\r';
	line[len++] = '\n';
			
	// write to file
	write(fd, line, len);
	
	close(fd);
}


static inline void datafile_append(struct datafile *d, char *id, char *timestr)
{
	if (d->write)
		write_data(datafolder, d->name, id, timestr, utc, d->data, d->nchan);
}


static struct datalogger datalogger;


static void onerror(int level, const char *msg)
{
	SetCtrlVal(MainPanel, PANEL_ERROR, 1);
}


static void * muParserNew()
{
	void *parser = mupCreate();
	
	mupDefineOprtChars(parser, "abcdefghijklmnopqrstuvwxyzµ"
                        	   "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                        	   "+-*^/?<>=#!$%&|~'_");
	
	mupDefineVar(parser, "Ch1", &Ch1);
	mupDefineVar(parser, "Ch2", &Ch2);
	mupDefineVar(parser, "Ch3", &Ch3);
	mupDefineVar(parser, "Ch4", &Ch4);
	mupDefineVar(parser, "DDS1", &(ad9912.frequency[0]));
	mupDefineVar(parser, "DDS2", &(ad9912.frequency[1]));
	mupDefineVar(parser, "DDS3", &(ad9912.frequency[2]));
	mupDefineVar(parser, "DDS4", &(ad9912.frequency[3]));
	mupDefineVar(parser, "N1", &N1);
	mupDefineVar(parser, "N2", &N2);
	mupDefineVar(parser, "N3", &N3);
	mupDefineVar(parser, "Sign1", &Sign1);
	mupDefineVar(parser, "Sign2", &Sign2);
	mupDefineVar(parser, "Sign3", &Sign3);
	mupDefineVar(parser, "Ndiv", &Ndiv);
	
	mupDefinePostfixOprt(parser, "P", &Peta,  1);
	mupDefinePostfixOprt(parser, "T", &Tera,  1);
	mupDefinePostfixOprt(parser, "G", &Giga,  1);
	mupDefinePostfixOprt(parser, "M", &Mega,  1);
	mupDefinePostfixOprt(parser, "k", &kilo,  1);
	mupDefinePostfixOprt(parser, "m", &milli, 1);
	mupDefinePostfixOprt(parser, "u", &micro, 1);
	mupDefinePostfixOprt(parser, "µ", &micro, 1);
	mupDefinePostfixOprt(parser, "n", &nano,  1);
	mupDefinePostfixOprt(parser, "p", &pico,  1);
	mupDefinePostfixOprt(parser, "f", &femto, 1);
	
	return parser;
}


void CVICALLBACK DataAvailableCB (CmtTSQHandle queueHandle, unsigned int event,
		int value, void *callbackData);


int main (int argc, char *argv[])
{
	int rv;
	double frequency;
	char expr[1024];
	char host[256];
	double clock;

	if ((MainPanel = LoadPanel (0, "FXAnalyse.uir", PANEL)) < 0)
		return -1;
	if ((CalcNPanel = LoadPanel (MainPanel, "FXAnalyse.uir", CALCN)) < 0)
		return -1;
	if ((EstimateNPanel = LoadPanel (MainPanel, "FXAnalyse.uir", ESTIMATEN)) < 0)
		return -1;

	// logging
	logger_init(&onerror);
	
	// load configuration file
	char path[MAX_PATHNAME_LEN];
	GetIniFilePath(path);
	IniText configuration = Ini_New(TRUE);
	Ini_ReadFromFile(configuration, path);

	// data folder
	rv = Ini_GetStringCopy(configuration, "data", "folder", &datafolder);
	if (rv > 0) {
		logmessage(INFO, "writing data files in %s", datafolder);
	} else {
		logmessage(ERROR, "data folder not configured in %s", path);
		// do not allow to start the acquisition
		SetCtrlAttribute(MainPanel, PANEL_STARTBUTTON, ATTR_DIMMED, TRUE);
	}
	
	// ad9956 configuration parameters
	rv = Ini_GetStringIntoBuffer(configuration, "AD9956", "host", host, sizeof(host));
	if (! rv)
		return -1;
	rv = Ini_GetDouble(configuration, "AD9956", "clock", &clock);
	if (! rv)
		return -1;
	
	// initialize AD9956 dedrift DDS
	rv = ad9956_init(&ad9956, host, clock);
	if (rv)
		logmessage(ERROR, "ad9956 init erorr=%d", -rv);
	ad9956_set_w(&ad9956, dedrift.fDDS, dedrift.applied);
	
	// ad9912 configuration parameters
	rv = Ini_GetStringIntoBuffer(configuration, "AD9912", "host", host, sizeof(host));
	if (! rv)
		return -1;
	rv = Ini_GetDouble(configuration, "AD9912", "clock", &clock);
	if (! rv)
		return -1;
	
	// initialize AD9912 DDS box
	rv = ad9912_init(&ad9912, host, clock);
	if (rv)
		logmessage(ERROR, "ad9912 init erorr=%d", -rv);
	
	GetCtrlVal(MainPanel, PANEL_DDS1, &frequency);
	ad9912_set_frequency_w(&ad9912, 0, frequency);
	GetCtrlVal(MainPanel, PANEL_DDS2, &frequency);
	ad9912_set_frequency_w(&ad9912, 1, frequency);
	GetCtrlVal(MainPanel, PANEL_DDS3, &frequency);
	ad9912_set_frequency_w(&ad9912, 2, frequency);
	GetCtrlVal(MainPanel, PANEL_DDS4, &frequency);
	ad9912_set_frequency_w(&ad9912, 3, frequency);
	
	// dispose configuration
	Ini_Dispose(configuration);

	// Sr data logger
	sr_datalogger_init(&datalogger);
	
	GetCtrlVal(MainPanel, PANEL_N1, &N1);
	GetCtrlVal(MainPanel, PANEL_N2, &N2);
	GetCtrlVal(MainPanel, PANEL_N3, &N3);

	MathParser1 = muParserNew();
	GetCtrlVal(MainPanel, PANEL_MATHSTRING1, expr);
	mupSetExpr(MathParser1, expr);
	
	MathParser2 = muParserNew();
	mupDefineVar(MathParser2, "Math1", &Math1);
	GetCtrlVal(MainPanel, PANEL_MATHSTRING2, expr);
	mupSetExpr(MathParser2, expr);
	
	MathParser3 = muParserNew();
	mupDefineVar(MathParser3, "Math1", &Math1);
	mupDefineVar(MathParser3, "Math2", &Math2);
	GetCtrlVal(MainPanel, PANEL_MATHSTRING3, expr);
	mupSetExpr(MathParser3, expr);
	
	MathParser4 = muParserNew();
	mupDefineVar(MathParser4, "Math1", &Math1);
	mupDefineVar(MathParser4, "Math2", &Math2);
	mupDefineVar(MathParser4, "Math3", &Math3);
	GetCtrlVal(MainPanel, PANEL_MATHSTRING4, expr);
	mupSetExpr(MathParser4, expr);
	
	MathParser5 = muParserNew();
	mupDefineVar(MathParser5, "Math1", &Math1);
	mupDefineVar(MathParser5, "Math2", &Math2);
	mupDefineVar(MathParser5, "Math3", &Math3);
	mupDefineVar(MathParser5, "Math4", &Math4);
	GetCtrlVal(MainPanel, PANEL_MATHSTRING5, expr);
	mupSetExpr(MathParser5, expr);
	
	// data queue
	CmtNewTSQ(128, sizeof(struct event), 0, &dataQueue);

	// register callback to execute when data will be in the data queue
	CmtInstallTSQCallback(dataQueue, EVENT_TSQ_ITEMS_IN_QUEUE, 1,
		DataAvailableCB, NULL, CmtGetCurrentThreadID(), NULL);
	
	DisplayPanel(MainPanel);
	
	RunUserInterface();
	
	DiscardPanel(MainPanel);
	return 0;
}

int CVICALLBACK QuitCallback (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			QuitUserInterface(0);
			break;
	}
	return 0;
}

int CVICALLBACK CB_OnEventMain(int panel, int event,
		void *callbackData, int eventData1, int eventData2)
{
	int control, index;
	double step;
	
#define do_arrow(__DDS, __STEP)										\
	do {															\
		GetCtrlIndex(panel, __STEP, &index);						\
		if ((eventData1 == VAL_RIGHT_ARROW_VKEY) && (index < 14))	\
			SetCtrlIndex(panel, __STEP, index + 1);					\
		if ((eventData1 == VAL_LEFT_ARROW_VKEY) && (index > 0))		\
			SetCtrlIndex(panel, __STEP, index - 1);					\
		GetCtrlVal(panel, __STEP, &step);							\
		SetCtrlAttribute(panel, __DDS, ATTR_INCR_VALUE, step);  	\
	} while (0) 
	
	switch (event) {
		case EVENT_KEYPRESS:
			/* key code */
			switch (eventData1) {
				case VAL_RIGHT_ARROW_VKEY:
				case VAL_LEFT_ARROW_VKEY:					
					control = GetActiveCtrl(panel);
					switch (control) {
						case PANEL_DDS1:
						case PANEL_DDS1STEP:
							do_arrow(PANEL_DDS1, PANEL_DDS1STEP);
							break;
						case PANEL_DDS2:
						case PANEL_DDS2STEP:
							do_arrow(PANEL_DDS2, PANEL_DDS2STEP);
							break;
						case PANEL_DDS3:
						case PANEL_DDS3STEP:
							do_arrow(PANEL_DDS3, PANEL_DDS3STEP);
							break;
						case PANEL_DDS4:
						case PANEL_DDS4STEP:
							do_arrow(PANEL_DDS4, PANEL_DDS4STEP);
							break;
					}
					break;
				case VAL_F2_VKEY :
					SetActiveCtrl(panel, PANEL_DDS1);
					break;
				case VAL_F3_VKEY :
					SetActiveCtrl(panel, PANEL_DDS2);
					break;
				case VAL_F4_VKEY :
					SetActiveCtrl(panel, PANEL_DDS3);
					break;
				case VAL_F5_VKEY :
					SetActiveCtrl(panel, PANEL_DDS4);
					break;
			}
			break;
	}
	return 0;
}

int CVICALLBACK CB_OnStart (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			if (acquiring)
				break;

			logmsg("start");
			SetCtrlAttribute(panel, PANEL_STARTBUTTON, ATTR_DIMMED, TRUE);
			acquiring = 1;
			
			// start data provider thread
			CmtScheduleThreadPoolFunctionAdv(
				DEFAULT_THREAD_POOL_HANDLE, DataProvider, NULL,
				THREAD_PRIORITY_HIGHEST, NULL, 0, NULL, 0, &dataProviderThread);

			break;
	}
	return 0;
}

int CVICALLBACK CB_OnStop (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event) {
		case EVENT_COMMIT:
			if (! acquiring)
				break;
			
			logmsg("stop");
			acquiring = 0;

			// wait for data provider thread to terminate
			CmtWaitForThreadPoolFunctionCompletion(
				DEFAULT_THREAD_POOL_HANDLE, dataProviderThread,
				OPT_TP_PROCESS_EVENTS_WHILE_WAITING);
			CmtReleaseThreadPoolFunctionID(
				DEFAULT_THREAD_POOL_HANDLE, dataProviderThread);

			SetCtrlAttribute(panel, PANEL_STARTBUTTON, ATTR_DIMMED, FALSE);
			
			break;
	}
	return 0;
}

void CVICALLBACK DataAvailableCB (CmtTSQHandle queueHandle, unsigned int ev,
		int value, void *callbackData)
{
	int read;
	
	switch (ev) {
		case EVENT_TSQ_ITEMS_IN_QUEUE:
			// read data from the data queue
			while (value > 0) {
				
				read = CmtReadTSQData(queueHandle, &event, 1, TSQ_INFINITE_TIMEOUT, 0);
				if (read != 1)
					logmsg("Error!");
				value = value - read;
				
				// unpack event
				utc = event.time.tv_sec + event.time.tv_usec * 1e-6;
				Ch1 = event.data[0];
				Ch2 = event.data[1];
				Ch3 = event.data[2];
				Ch4 = event.data[3];

				// update display
				SetCtrlVal(MainPanel, PANEL_UTC, utc);
				SetCtrlVal(MainPanel, PANEL_CH1, Ch1);
				SetCtrlVal(MainPanel, PANEL_CH2, Ch2);
				SetCtrlVal(MainPanel, PANEL_CH3, Ch3);  
				SetCtrlVal(MainPanel, PANEL_CH4, Ch4);

				// compute
				Math1 = mupEval(MathParser1);
				Math2 = mupEval(MathParser2);
				Math3 = mupEval(MathParser3);
				Math4 = mupEval(MathParser4);
				Math5 = mupEval(MathParser5);
				
				// update display.  numeric controllers do not format values
				// with a thousands separator: use string controllers and a 
				// custom formatting function
				char buffer[256];
				SetCtrlVal(MainPanel, PANEL_MATH1, thousands(buffer, sizeof(buffer), "%.6f", Math1));
				SetCtrlVal(MainPanel, PANEL_MATH2, thousands(buffer, sizeof(buffer), "%.3f", Math2));
				SetCtrlVal(MainPanel, PANEL_MATH3, thousands(buffer, sizeof(buffer), "%.3f", Math3));
				SetCtrlVal(MainPanel, PANEL_MATH4, thousands(buffer, sizeof(buffer), "%.3f", Math4));
				SetCtrlVal(MainPanel, PANEL_MATH5, thousands(buffer, sizeof(buffer), "%.3f", Math5));

				// update timeseries plots
				for (struct plot *plot = plots; plot->data; plot++)
					plot_update(plot);

				// update allan deviation plots
				for (struct adev *adev = adevs; adev->data; adev++)
					adev_update(adev);
				
				// N measurement

				switch (n_measurement_1) {
					
					case N_MEASUREMENT_NONE:
						// not measuring
						break;
					
					case N_MEASUREMENT_INIT:
						// initialization step
						
						// set DDS1 to nominal frequency
						ad9912_set_frequency_w(&ad9912, 0, f0_DDS1);
						SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
						
						// record current DDS frequencies
						f0_DDS2 = ad9912.frequency[1];
						
						t1 = utc;
						t2 = t3 = 0.0;
						nobs = 0;
						stat_zero(&stat_math1);
						f_rep_plus = f_rep_minus = 0.0;
						
						// next step
						n_measurement_1 += 1;
						break;
						
					case N_MEASUREMENT_SLOPE:
						// slope measurement
						
						stat_accumulate(&stat_math1, Math1);
						
						if ((utc - t1) > slope_time_1) {
							f_rep_slope = stat_math1.slope;
							
							// frep positive step
							ad9912_ramp_frequency_w(&ad9912, 0, f0_DDS1 + delta_f_lock_1, FREP_STEP_SIZE);
							SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
							
							// allow counter to settle
							settling = 3;
							
							// next step
							n_measurement_1 += 1;
						}
						break;
						
					case N_MEASUREMENT_ADJUST_FREQ_PLUS:
					case N_MEASUREMENT_ADJUST_FREQ_MINUS:
						// adjust DDS frequency to keep beatnote within the bandpass filter
						
						if (settling-- > 0)
							break;
						
						double fDDS2 = ad9912.frequency[1];
						ad9912_set_frequency_w(&ad9912, 1, fDDS2 + 275000 - Ch4);
						SetCtrlVal(MainPanel, PANEL_DDS2, ad9912.frequency[1]);
						
						// allow counter to settle
						settling = 3;
						
						// next step
						n_measurement_1 += 1;
						break;								
						
					case N_MEASUREMENT_FREP_PLUS:
						// frep positive step
						
						if (settling-- > 0)
							break;
						
						if (t2 == 0.0)
							t2 = utc;
						
						f_rep_plus += Math1 - f_rep_slope * (utc - t2);
						nobs += 1;
						
						if ((utc - t2) > integration_time_1) {
							f_rep_plus = f_rep_plus / nobs;
							nobs = 0;
							
							// frep negative step
							ad9912_ramp_frequency_w(&ad9912, 0, f0_DDS1 - delta_f_lock_1, FREP_STEP_SIZE);
							SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
							
							// allow counter to settle
							settling = 3;
							
							// next step
							n_measurement_1 += 1;
						}
						break;
						
					case N_MEASUREMENT_FREP_MINUS:
						// frep negative step
						
						if (settling-- > 0)
							break;
						
						if (t3 == 0.0)
							t3 = utc;
						
						f_rep_minus += Math1 - f_rep_slope * (utc - t2);
						nobs += 1;
						
						if ((utc - t3) > integration_time_1) {
							f_rep_minus = f_rep_minus / nobs;
							nobs = 0;
							
							// compute N1
							double delta_f_rep = f_rep_minus - f_rep_plus;
							double measured = Sign1 * 2 * Ndiv * delta_f_lock_1 / delta_f_rep;
							SetCtrlVal(CalcNPanel, CALCN_N, measured);
							
							// back to nominal frep
							ad9912_ramp_frequency_w(&ad9912, 0, f0_DDS1, FREP_STEP_SIZE);
							ad9912_set_frequency_w(&ad9912, 1, f0_DDS2);
							SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
							SetCtrlVal(MainPanel, PANEL_DDS2, ad9912.frequency[1]);
							
							// done
							n_measurement_1 = N_MEASUREMENT_NONE;
						}
						break;
				}

				switch (n_measurement_2) {

					case N_MEASUREMENT_NONE:
						// not measuring
						break;
					
					case N_MEASUREMENT_INIT:
						// initialization step
						
						// set DDS1 to nominal frequency
						ad9912_set_frequency_w(&ad9912, 0, f0_DDS1);
						SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
						
						// record current DDS frequencies
						f0_DDS2 = ad9912.frequency[1];
						f0_DDS3 = ad9912.frequency[2];
						
						t1 = utc;
						t2 = t3 = 0.0;
						nobs = 0;
						stat_zero(&stat_math1);
						stat_zero(&stat_ch2);
						f_rep_plus = f_rep_minus = 0.0;
						f_beat_plus = f_beat_minus = 0.0;
						
						// next step
						n_measurement_2 += 1;
						break;
						
					case N_MEASUREMENT_SLOPE:
						// slope measurement
						
						stat_accumulate(&stat_math1, Math1);
						stat_accumulate(&stat_ch2, Ch2);

						if ((utc - t1) > slope_time_2) {
							f_rep_slope = stat_math1.slope;
							f_beat_slope = stat_ch2.slope;
							
							// frep positive step
							double fDDS1 = f0_DDS1 + delta_f_lock_2;
							ad9912_ramp_frequency_w(&ad9912, 0, fDDS1, FREP_STEP_SIZE);
							SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
							
							// adjust DDS3 to keep beatnote within the bandpass filter. prediction
							double fDDS3 = f0_DDS3 + Sign1 * Sign2 * N2/N1 * Ndiv * delta_f_lock_2;
							df_DDS3 = fDDS3 - ad9912.frequency[2];
							ad9912_set_frequency_w(&ad9912, 2, fDDS3);
							SetCtrlVal(MainPanel, PANEL_DDS3, ad9912.frequency[2]);
						
							// allow counter to settle
							settling = 3;
							
							// next step
							n_measurement_2 += 1;
						}
						break;

					case N_MEASUREMENT_ADJUST_FREQ_PLUS:
					case N_MEASUREMENT_ADJUST_FREQ_MINUS:
						// adjust DDS frequency to keep beatnote within the bandpass filter
						
						if (settling-- > 0)
							break;
						
						double fDDS2 = ad9912.frequency[1] + 275000 - Ch4;
						ad9912_set_frequency_w(&ad9912, 1, fDDS2);
						SetCtrlVal(MainPanel, PANEL_DDS2, ad9912.frequency[1]);
						
						double fDDS3 = ad9912.frequency[2] + 10000 - Ch2;
						df_DDS3 = df_DDS3 + 10000 - Ch2;
						ad9912_set_frequency_w(&ad9912, 2, fDDS3);
						SetCtrlVal(MainPanel, PANEL_DDS3, ad9912.frequency[2]);

						// allow counter to settle
						settling = 3;

						// next step
						n_measurement_2 += 1;
						break;
						
					case N_MEASUREMENT_FREP_PLUS:
						// frep positive step
						
						if (settling-- > 0)
							break;

						if (t2 == 0.0)
							t2 = utc;

						f_rep_plus += Math1 + 250000000 - f_rep_slope * (utc - t2);
						f_beat_plus += Ch2 - f_beat_slope * (utc - t2);
						nobs += 1;
						
						if ((utc - t2) > integration_time_2) {
							f_rep_plus = f_rep_plus / nobs;
							f_beat_plus = f_beat_plus / nobs;
							nobs = 0;

							// negative frequency step
							double fDDS1 = f0_DDS1 - delta_f_lock_2;
							ad9912_ramp_frequency_w(&ad9912, 0, fDDS1, FREP_STEP_SIZE);
							SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
							
							// adjust DDS3 to keep beatnote within the bandpass filter. prediction
							double fDDS3 = f0_DDS3 - Sign1 * Sign2 * N2/N1 * Ndiv * delta_f_lock_2;
							df_DDS3 = fDDS3 - ad9912.frequency[2];
							ad9912_set_frequency_w(&ad9912, 2, fDDS3);
							SetCtrlVal(MainPanel, PANEL_DDS3, ad9912.frequency[2]);

							// allow counter to settle
							settling = 3;
							
							// next step
							n_measurement_2 += 1;
						}
						break;
						
					case N_MEASUREMENT_FREP_MINUS:
						// frep negative step
						
						if (settling-- > 0)
							break;
						
						if (t3 == 0.0)
							t3 = utc;

						f_rep_minus += Math1 + 250000000 - f_rep_slope * (utc - t2);
						f_beat_minus += Ch2 + f_beat_slope * (utc - t2);
						nobs += 1;

						if ((utc -t3) > integration_time_2) {
							f_rep_minus = f_rep_minus / nobs;
							f_beat_minus = f_beat_minus / nobs;
							nobs = 0;

							// compute N2
							double delta_f_rep_m = f_rep_minus - f_rep_plus;
							double delta_f_rep = Sign1 * Ndiv * 2.0 * delta_f_lock_2 / N1;
							double delta = delta_f_rep_m - delta_f_rep;
							
							logmsg("delta frep: measured=%e expected=%e difference=%e rel=%e",
								delta_f_rep_m, delta_f_rep, delta, delta / delta_f_rep);
							
							double measured = -Sign2 * (df_DDS3 + f_beat_minus - f_beat_plus) / delta_f_rep;
							SetCtrlVal(CalcNPanel, CALCN_N, measured);
							
							// back to nominal frequency
							ad9912_ramp_frequency_w(&ad9912, 0, f0_DDS1, FREP_STEP_SIZE);
							ad9912_set_frequency_w(&ad9912, 1, f0_DDS2);
							ad9912_set_frequency_w(&ad9912, 2, f0_DDS3);
							SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
							SetCtrlVal(MainPanel, PANEL_DDS2, ad9912.frequency[1]);
							SetCtrlVal(MainPanel, PANEL_DDS3, ad9912.frequency[2]);
							
							// done
							n_measurement_2 = N_MEASUREMENT_NONE;
						}
						break;
				}
				
				switch (n_measurement_3) {
					
					case N_MEASUREMENT_NONE:
						// not measuring N3
						break;
						
					case N_MEASUREMENT_INIT:
						// init
						
						// set DDS1 to nominal frequency
						ad9912_set_frequency_w(&ad9912, 0, f0_DDS1);
						SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
						
						// record current DDS frequencies
						f0_DDS2 = ad9912.frequency[1];
						f0_DDS4 = ad9912.frequency[3];
						
						t1 = utc;
						t2 = t3 = 0.0;
						nobs = 0;
						stat_zero(&stat_math1);
						stat_zero(&stat_ch3);
						f_rep_plus = f_rep_minus = 0.0;
						f_beat_plus = f_beat_minus = 0.0;
						
						// next step
						n_measurement_3 += 1;
						break;
						
					case N_MEASUREMENT_SLOPE:
						// slope measurement
						
						if (settling-- > 0)
							break;
						
						stat_accumulate(&stat_math1, Math1);
						stat_accumulate(&stat_ch3, Ch3);
						
						if (utc - t1 > slope_time_3) {
							// slope measurement
							f_rep_slope = stat_math1.slope;
							f_beat_slope = stat_ch3.slope;
							
							logmsg("f_rep_slope=%e Hz/s", f_rep_slope);
							logmsg("f_beat_slope=%e Hz/s", f_rep_slope);
							
							// frep positive step
							ad9912_ramp_frequency_w(&ad9912, 0, f0_DDS1 + delta_f_lock_3, FREP_STEP_SIZE);
							SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
							
							// adjust DDS3 to keep beatnote within the bandpass filter
							double fDDS4 = f0_DDS4 + Sign1 * Sign3 * N3/N1 * Ndiv * delta_f_lock_3;
							ad9912_set_frequency_w(&ad9912, 3, fDDS4);
							SetCtrlVal(MainPanel, PANEL_DDS4, ad9912.frequency[3]);
							
							// allow counter to settle
							settling = 3;
							
							// next step
							n_measurement_3 += 1;
						}
						break;

					case N_MEASUREMENT_ADJUST_FREQ_PLUS:
					case N_MEASUREMENT_ADJUST_FREQ_MINUS:
						// adjust DDS frequency to keep beatnote within the bandpass filter

						if (settling-- > 0)
							break;
						
						// adjust DDS frequency to keep 55 MHz tracker oscillator locked
						double fDDS2 = ad9912.frequency[1] + 275000 - Ch4;
						ad9912_set_frequency_w(&ad9912, 1, fDDS2);
						SetCtrlVal(MainPanel, PANEL_DDS2, ad9912.frequency[1]);
						
						// allow counter to settle
						settling = 3;
						
						// next step
						n_measurement_3 += 1;
						break;						
						
					case N_MEASUREMENT_FREP_PLUS:
						// frep positive step
						
						if (settling-- > 0)
							break;

						if (t2 == 0.0)
							t2 = utc;
						
						f_rep_plus += Math1 + 250000000 - f_rep_slope * (utc - t2);
						f_beat_plus += Ch3 - f_beat_slope * (utc - t2);
						nobs += 1;
						
						if (utc - t2 > integration_time_3) {
							f_rep_plus = f_rep_plus / nobs;
							f_beat_plus = f_beat_plus / nobs;
							nobs = 0;
							
							// frep negative step
							ad9912_ramp_frequency_w(&ad9912, 0, f0_DDS1 - delta_f_lock_3, FREP_STEP_SIZE);
							SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);

							// adjust DDS3 to keep beatnote within the bandpass filter
							double fDDS4 = f0_DDS4 - Sign1 * Sign3 * N3/N1 * Ndiv * delta_f_lock_3;
							ad9912_set_frequency_w(&ad9912, 3, fDDS4);
							SetCtrlVal(MainPanel, PANEL_DDS4, ad9912.frequency[3]);
							
							// allow counter to settle
							settling = 3;
							
							// next step
							n_measurement_3 += 1;
						}
						break;
					
					case N_MEASUREMENT_FREP_MINUS:
						// frep negative step
						
						if (settling-- > 0)
							break;
						
						if (t3 == 0.0)
							t3 = utc;
						
						f_rep_minus += Math1 + 250000000 - f_rep_slope * (utc - t2);
						f_beat_minus += Ch3 - f_beat_slope * (utc - t2);
						nobs += 1;
						
						if (utc - t3 > integration_time_3) {
							f_rep_minus = f_rep_minus / nobs;
							f_beat_minus = f_beat_minus / nobs;
							nobs = 0;
							
							// check delta frep
							double delta_f_rep_m = f_rep_minus - f_rep_plus;
							double delta_f_rep = Sign1 * Ndiv * 2.0 * delta_f_lock_3 / N1;
							double delta = delta_f_rep_m - delta_f_rep;
							
							logmsg("delta frep: measured=%e expected=%e difference=%e rel=%e",
								delta_f_rep_m, delta_f_rep, delta, delta / delta_f_rep);
							
							// compute N3
							double delta_f_beat = f_beat_minus - f_beat_plus + 2.0 * Sign1 * Sign3 * N3/N1 * Ndiv * delta_f_lock_3;
							double delta_f_beat_expected = delta_f_rep * N3;
							
							logmsg("delta fbeat: measured=%e expected=%e difference=%e",
								delta_f_beat, delta_f_beat_expected, delta_f_beat - delta_f_beat_expected);
							
							double measured = delta_f_beat / delta_f_rep;
							SetCtrlVal(CalcNPanel, CALCN_N, measured);
							
							logmsg("measured N3=%.3f", measured);
							
							// back to nominal frep
							ad9912_ramp_frequency_w(&ad9912, 0, f0_DDS1, FREP_STEP_SIZE);
							ad9912_set_frequency_w(&ad9912, 1, f0_DDS2);
							ad9912_set_frequency_w(&ad9912, 3, f0_DDS4);
							SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
							SetCtrlVal(MainPanel, PANEL_DDS2, ad9912.frequency[1]);
							SetCtrlVal(MainPanel, PANEL_DDS4, ad9912.frequency[3]);
							
							// done
							n_measurement_3 = N_MEASUREMENT_NONE;
						}
						break;
				}
				
				// beatnote sign determination				
				if ((beatsign.measure) && 
				    (utc > beatsign.t0 + 2.0)) {

					int f_beat_sign, f_rep_sign = 0; 
					
					switch (beatsign.measure) {
					case LO:
						f_rep_sign = (Math1 > beatsign.f_rep_zero) ? -1 : 1;
						Sign1 = f_rep_sign;
						SetCtrlVal(MainPanel, PANEL_SIGN1, Sign1);
						break;
					case HG:
						f_rep_sign = (Math1 > beatsign.f_rep_zero) ? -1 : 1;
						f_beat_sign = (Ch2 > beatsign.f_beat_zero) ? -1 : 1;
						Sign2 = f_rep_sign * f_beat_sign;
						SetCtrlVal(MainPanel, PANEL_SIGN2, Sign2);
						break;
					case SR:
						f_rep_sign = (Math1 > beatsign.f_rep_zero) ? -1 : 1;
						f_beat_sign = (Ch3 > beatsign.f_beat_zero) ? -1 : 1;
						Sign3 = f_rep_sign * f_beat_sign;
						SetCtrlVal(MainPanel, PANEL_SIGN3, Sign3);
						break;
					}

					// back to original repetition rate
					ad9912_set_frequency_w(&ad9912, 0, beatsign.f0_DDS1);
					SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);

					// measurement done
					beatsign.measure = 0;
						
					// in the case of the optical beatnotes sign measurement
					// we induce fairly small steps in f_rep therefore it is
					// good to check that we get the sign of the comb locking 
					// beatnote right in those cases
					if (f_rep_sign != Sign1)
						logmessage(ERROR, "merasured f_rep_sign does not agree with previous determination!");
				}
				
				// select dedrift reference
				double f = 0.0;
				switch (dedrift.reference) {
					case DEDRIFT_REFERENCE_MICROWAVE:
						f = Math2;
						break;
					case DEDRIFT_REFERENCE_HG:
						f = Ch2 * 1062.5 / 1542.2;
						break;
				}

				// dedrift
				dedrift_update(f);
								
				// recenter
				if (recenter.enabled)
				{
					rollmean_accumulate(&rollmean_ch2, Ch2);
					rollmean_accumulate(&rollmean_ch3, Ch3);
					rollmean_accumulate(&rollmean_ch4, Ch4);
					
					if ((utc - recenter.t0) > recenter.interval) {
		
						if (recenter.lo) {
							// adjust DDS2 frequency to keep Ch4 reading at 275 kHz
							double freq = ad9912.frequency[1];
							double adj = 275000.0 - rollmean_ch4.mean;
							freq = freq + adj;
							ad9912_set_frequency_w(&ad9912, 1, freq);
							SetCtrlVal(MainPanel, PANEL_DDS2, ad9912.frequency[1]);
							logmsg("recenter ch4 to 275 kHz: DDS2 adjustment=%+3e", adj);
						}
					
						if (recenter.hg) {
							// adjust DDS3 frequency to keep Ch2 reading at 10 kHz
							double freq = ad9912.frequency[2];
							double adj = 10000 - rollmean_ch2.mean;
							freq = freq + adj;
							ad9912_set_frequency_w(&ad9912, 2, freq);
							SetCtrlVal(MainPanel, PANEL_DDS3, ad9912.frequency[2]);
							logmsg("recenter Hg beatnote (ch2) to 10 kHz: DDS3 adjustment=%+3e", adj);
						}
					
						if (recenter.sr) {
							// adjust DDS4 frequency to keep Ch3 reading at 10 kHz
							double freq = ad9912.frequency[3];
							double adj = 10000 - rollmean_ch3.mean;
							freq = freq + adj;
							ad9912_set_frequency_w(&ad9912, 3, freq);
							SetCtrlVal(MainPanel, PANEL_DDS4, ad9912.frequency[3]);
							logmsg("recenter Sr beatnote (ch3) to 10 kHz: DDS4 adjustment=%+3e", adj);
						}
					
						recenter.t0 = utc;
						rollmean_zero(&rollmean_ch2);
						rollmean_zero(&rollmean_ch3);
						rollmean_zero(&rollmean_ch4);
					}
				}

				// local time
				struct tm *ltime = localtime(&event.time.tv_sec);
				// round to milliseconds
				int msec = round(event.time.tv_usec / 1000.0);
				while (msec >= 1000) {
					ltime->tm_sec += 1;
					msec -= 1000;
				}
				// format local time
				char timestr[24];
				int len = strftime(timestr, sizeof(timestr), "%d/%m/%Y %H:%M:%S", ltime);
				snprintf(timestr + len, sizeof(timestr) - len, ".%03d", msec);
				// display local time
				SetCtrlVal(MainPanel, PANEL_TIME, timestr);
				
				// run id derived from current local date in the form YYMMDD
				char id[7];
				strftime(id, sizeof(id), "%y%m%d", ltime);
				
				// write datafiles
				for (struct datafile *d = datafiles; d->data; d++)
					datafile_append(d, id, timestr);
				
				// send Sr frequency (Math4) to Sr data logger
				sr_datalogger_send(&datalogger, utc, Math4);
			}		
			break;
	}
}

int CVICALLBACK CB_OnFreqPlot (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			for (struct plot *plot = plots; plot->data; plot++) {
				if (plot->control == control)
					plot_toggle(plot);
			}
			break;
	}
	return 0;
}

int CVICALLBACK CB_OnAllanPlot (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			for (struct adev *adev = adevs; adev->data; adev++) {
				if (adev->control == control)
					adev_toggle(adev);
			}
			break;
	}
	return 0;
}

int  CVICALLBACK CB_ChangeDDSOut (int panel, int control, int event, 
		 void *callbackData, int eventData1, int eventData2)
{
	switch (event) {
		case EVENT_COMMIT:
			double frequency;
			GetCtrlVal(MainPanel, control, &frequency);
			switch (control) {
				case PANEL_DDS1:
					ad9912_set_frequency_w(&ad9912, 0, frequency);
					SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
					break;
				case PANEL_DDS2:
					ad9912_set_frequency_w(&ad9912, 1, frequency);
					SetCtrlVal(MainPanel, PANEL_DDS2, ad9912.frequency[1]);
					break;
				case PANEL_DDS3:
					ad9912_set_frequency_w(&ad9912, 2, frequency);
					SetCtrlVal(MainPanel, PANEL_DDS3, ad9912.frequency[2]);
					break;
				case PANEL_DDS4:
					ad9912_set_frequency_w(&ad9912, 3, frequency);
					SetCtrlVal(MainPanel, PANEL_DDS4, ad9912.frequency[3]);
					break;
			}
			break;
	}
	return 0;
}

int  CVICALLBACK CB_ChangeDDSStep (int panel, int control, int event, 
		 void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			double step;
			GetCtrlVal(panel, control, &step);
			switch (control)
			{
				case PANEL_DDS1STEP:
					SetCtrlAttribute(panel, PANEL_DDS1, ATTR_INCR_VALUE, step);
					break;
				case PANEL_DDS2STEP:
					SetCtrlAttribute(panel, PANEL_DDS2, ATTR_INCR_VALUE, step);
					break;
				case PANEL_DDS3STEP:
					SetCtrlAttribute(panel, PANEL_DDS3, ATTR_INCR_VALUE, step);
					break;
				case PANEL_DDS4STEP:
					SetCtrlAttribute(panel, PANEL_DDS4, ATTR_INCR_VALUE, step);
					break;
			}
			break;
	}
	return 0;
}

int CVICALLBACK CB_ChangeMath (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	int len;
	char *string;
		
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlAttribute(panel, control, ATTR_STRING_TEXT_LENGTH, &len);
			string = (char *)malloc(sizeof(char) * (len + 1));
			GetCtrlVal(panel, control, string);
			switch (control) {
				case PANEL_MATHSTRING1:
					mupSetExpr(MathParser1, string);
					break;
				case PANEL_MATHSTRING2:
					mupSetExpr(MathParser2, string);
					break;
				case PANEL_MATHSTRING3:
					mupSetExpr(MathParser3, string);
					break;
				case PANEL_MATHSTRING4:
					mupSetExpr(MathParser4, string);
					break;
				case PANEL_MATHSTRING5:
					mupSetExpr(MathParser5, string);
					break;
			}
			free(string);
			break;
	}
	return 0;
}

int CVICALLBACK CB_ChangeN (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			switch (control)
			{
				case PANEL_N1:
					GetCtrlVal(panel, control, &N1);
					break;
				case PANEL_N2:
					GetCtrlVal(panel, control, &N2);
					break;
				case PANEL_N3:
					GetCtrlVal(panel, control, &N3);
					break;
			}
			break;
	}
	return 0;
}

int CVICALLBACK CB_OnAcceptN (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	int measure;
	double measured;

	switch (event) {
		case EVENT_COMMIT:
			GetPanelAttribute(panel, ATTR_CALLBACK_DATA, &measure);
			GetCtrlVal(panel, CALCN_N, &measured);
			switch (measure) {
				case LO:
					N1 = round(measured);
					SetCtrlVal(MainPanel, PANEL_N1, N1);
					break;
				case HG:
					N2 = round(measured);
					SetCtrlVal(MainPanel, PANEL_N2, N2);
					break;
				case SR:
					N3 = round(measured);
					SetCtrlVal(MainPanel, PANEL_N3, N3);
					break;
			} 
			break;
	}
	return 0;
}

int CVICALLBACK CB_OnNCalculus (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	int visible;
	
	switch (event) {
		case EVENT_COMMIT:
			switch (control) {
				case PANEL_N1CALCULUS:
					GetPanelAttribute(CalcNPanel, ATTR_VISIBLE, &visible);
					if (! visible) {
						SetPanelAttribute(CalcNPanel, ATTR_CALLBACK_DATA, INT_TO_PTR(LO));
						SetPanelAttribute(CalcNPanel, ATTR_TITLE, "Measure N_Lo");
						SetCtrlVal(CalcNPanel, CALCN_INTEGRATIONTIME, integration_time_1);
						SetCtrlVal(CalcNPanel, CALCN_SLOPETIME, slope_time_1);
						SetCtrlVal(CalcNPanel, CALCN_DELTAFREQ, delta_f_lock_1 / 1000.0);
						SetCtrlVal(CalcNPanel, CALCN_N, 0.0);
						DisplayPanel(CalcNPanel);
					}
					break;
				case PANEL_N2CALCULUS:
					GetPanelAttribute(CalcNPanel, ATTR_VISIBLE, &visible);
					if (! visible) {
						SetPanelAttribute(CalcNPanel, ATTR_CALLBACK_DATA, INT_TO_PTR(HG));
						SetPanelAttribute(CalcNPanel, ATTR_TITLE, "Measure N_Hg");
						SetCtrlVal(CalcNPanel, CALCN_INTEGRATIONTIME, integration_time_2);
						SetCtrlVal(CalcNPanel, CALCN_SLOPETIME, slope_time_2);
						SetCtrlVal(CalcNPanel, CALCN_DELTAFREQ, delta_f_lock_2 / 1000.0);
						SetCtrlVal(CalcNPanel, CALCN_N, 0.0);
						DisplayPanel(CalcNPanel);
					} 
					break;
				case PANEL_N3CALCULUS:
					GetPanelAttribute(CalcNPanel, ATTR_VISIBLE, &visible);
					if (! visible) {
						SetPanelAttribute(CalcNPanel, ATTR_CALLBACK_DATA, INT_TO_PTR(SR));
						SetPanelAttribute(CalcNPanel, ATTR_TITLE, "Measure N_Sr");
						SetCtrlVal(CalcNPanel, CALCN_INTEGRATIONTIME, integration_time_3);
						SetCtrlVal(CalcNPanel, CALCN_SLOPETIME, slope_time_3);
						SetCtrlVal(CalcNPanel, CALCN_DELTAFREQ, delta_f_lock_3 / 1000.0);
						SetCtrlVal(CalcNPanel, CALCN_N, 0.0);
						DisplayPanel(CalcNPanel);
					}
					break;
			}
			break;
	}
	return 0;
}

int CVICALLBACK CB_OnStartNCalculus (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	void *v;
	int measuring;
	
	switch (event) {
		case EVENT_COMMIT:
			GetPanelAttribute(panel, ATTR_CALLBACK_DATA, &v);
			measuring = PTR_TO_INT(v);
			switch (measuring) {
				case LO:
					GetCtrlVal(CalcNPanel, CALCN_INTEGRATIONTIME, &integration_time_1);
					GetCtrlVal(CalcNPanel, CALCN_SLOPETIME, &slope_time_1);
					GetCtrlVal(CalcNPanel, CALCN_DELTAFREQ, &delta_f_lock_1);
					// convert from kHz to Hz
					delta_f_lock_1 = delta_f_lock_1 * 1000.0;
					n_measurement_1 = TRUE;
					break;
				case HG:
					GetCtrlVal(CalcNPanel, CALCN_INTEGRATIONTIME, &integration_time_2);
					GetCtrlVal(CalcNPanel, CALCN_SLOPETIME, &slope_time_2);
					GetCtrlVal(CalcNPanel, CALCN_DELTAFREQ, &delta_f_lock_2);
					// convert from kHz to Hz
					delta_f_lock_2 = delta_f_lock_2 * 1000.0;
					n_measurement_2 = TRUE;
					break;
				case SR:
					GetCtrlVal(CalcNPanel, CALCN_INTEGRATIONTIME, &integration_time_3);
					GetCtrlVal(CalcNPanel, CALCN_SLOPETIME, &slope_time_3);
					GetCtrlVal(CalcNPanel, CALCN_DELTAFREQ, &delta_f_lock_3);
					// convert from kHz to Hz
					delta_f_lock_3 = delta_f_lock_3 * 1000.0;
					n_measurement_3 = TRUE;
					break;
			}
			break;
	}
	return 0;
}

int CVICALLBACK CB_OnNStop (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	void *v;
	int measuring;
	
	switch (event) {
		case EVENT_COMMIT:
			HidePanel(CalcNPanel);
			GetPanelAttribute(panel, ATTR_CALLBACK_DATA, &v);
			measuring = PTR_TO_INT(v);
			switch (measuring) {
				case LO:
					n_measurement_1 = FALSE;
					ad9912_ramp_frequency_w(&ad9912, 0, f0_DDS1, FREP_STEP_SIZE);
					ad9912_set_frequency_w(&ad9912, 1, f0_DDS2);
					break;
				case HG:
					n_measurement_2 = FALSE;
					ad9912_ramp_frequency_w(&ad9912, 0, f0_DDS1, FREP_STEP_SIZE);
					ad9912_set_frequency_w(&ad9912, 1, f0_DDS2);
					ad9912_set_frequency_w(&ad9912, 2, f0_DDS3);
					break;
				case SR:
					n_measurement_3 = FALSE;
					ad9912_ramp_frequency_w(&ad9912, 0, f0_DDS1, FREP_STEP_SIZE);
					ad9912_set_frequency_w(&ad9912, 1, f0_DDS2);
					ad9912_set_frequency_w(&ad9912, 3, f0_DDS4);
					break;
			}
			
			// update DDS frequencies display
			SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
			SetCtrlVal(MainPanel, PANEL_DDS2, ad9912.frequency[1]);
			SetCtrlVal(MainPanel, PANEL_DDS3, ad9912.frequency[2]);
			SetCtrlVal(MainPanel, PANEL_DDS4, ad9912.frequency[3]);
			
			break;
	}
	return 0;
}

int  CVICALLBACK CB_OnFindSign (int panel, int control, int event, 
		void *callbackData, int eventData1, int eventData2)
{
	double step = 0.0;
	switch (event)
	{
		case EVENT_COMMIT:
			switch (control) {
			        case PANEL_FINDSIGN1:
					beatsign.measure = LO;
					beatsign.f_beat_zero = 0.0;
					step = f_lock_step_1;
					break;
				case PANEL_FINDSIGN2:
					beatsign.measure = HG;
					beatsign.f_beat_zero = Ch2;
					step = f_lock_step_2;
					break;
				case PANEL_FINDSIGN3:
					beatsign.measure = SR;
					beatsign.f_beat_zero = Ch3;
					step = f_lock_step_3;
					break;
			}

			beatsign.t0 = utc;
			beatsign.f_rep_zero = Math1;

			// step the repetition rate
			beatsign.f0_DDS1 = ad9912.frequency[0];
			ad9912_set_frequency_w(&ad9912, 0, beatsign.f0_DDS1 + step);
			SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);

			break;
	}
	return 0;
}

int  CVICALLBACK CB_AdjustDDSFreq (int panel, int control, int event, 
		 void *callbackData, int eventData1, int eventData2)
{
	double frequency;
	switch (event)
	{
		case EVENT_COMMIT:
			switch (control)
			{
				case PANEL_ADJUST_DDS2:
					frequency = ad9912.frequency[1] + 275000 - Ch4;
					ad9912_set_frequency_w(&ad9912, 1, frequency);
					SetCtrlVal(MainPanel, PANEL_DDS2, ad9912.frequency[1]);
					break;
				case PANEL_ADJUST_DDS3:
					frequency = ad9912.frequency[2] + 10000 - Ch2;
					ad9912_set_frequency_w(&ad9912, 2, frequency);
					SetCtrlVal(MainPanel, PANEL_DDS3, ad9912.frequency[2]);
					break;
				case PANEL_ADJUST_DDS4:
					frequency = ad9912.frequency[3] + 10000 - Ch3;
					ad9912_set_frequency_w(&ad9912, 3, frequency);
					SetCtrlVal(MainPanel, PANEL_DDS4, ad9912.frequency[3]);
					break;
			}
			break;
	}
	return 0;
}

int  CVICALLBACK CB_OnChangeNdiv (int panel, int control, int event, 
		 void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(MainPanel, PANEL_CHANGENDIV, &Ndiv);
			f0_DDS1 = 880000000.0 / Ndiv;
			ad9912_set_frequency_w(&ad9912, 0, f0_DDS1);
			SetCtrlVal(MainPanel, PANEL_DDS1, ad9912.frequency[0]);
			break;
	}
	return 0;
}

int  CVICALLBACK CB_MeasureSlope (int panel, int control, int event, 
		 void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &dedrift.enabled);
			if (dedrift.enabled) {
				dedrift.t0 = utc;
				stat_zero(&dedrift.stat);
				logmsg("dedrift start");
			} else {
				if (! dedrift.keep_slope) {
					dedrift.applied = 0.0;
					ad9956_set_sweep_rate_w(&ad9956, dedrift.applied);
					SetCtrlVal(MainPanel, PANEL_SLOPE_APPLIED, dedrift.applied);
				}
				if (! dedrift.keep_freq) {
					ad9956_set_w(&ad9956, dedrift.fDDS, dedrift.applied);
				}
				stat_zero(&dedrift.stat);
				SetCtrlVal(panel, PANEL_SLOPE_MEASURED, dedrift.stat.slope);
				logmsg("dedrift stop");
			}
			break;
	}
	return 0;
}

int  CVICALLBACK CB_OnResetSlope (int panel, int control, int event, 
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			dedrift.applied = 0.0; 
			SetCtrlVal(panel, PANEL_SLOPE_APPLIED, dedrift.applied);
			ad9956_set_w(&ad9956, dedrift.fDDS, dedrift.applied);
			logmsg("dedrift reset");
			break;
	}
	return 0;
}
  
int  CVICALLBACK CB_ChangeSlopeTime (int panel, int control, int event, 
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(MainPanel, PANEL_SLOPETIME, &dedrift.interval); 
			break;
	}
	return 0;
}

int  CVICALLBACK CB_OnDedriftSettingsChange (int panel, int control, int event, 
		 void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			switch (control)
			{
				case PANEL_DEDRIFT_PROPORTIONAL:
					// include correction proportional to frequency
				   	GetCtrlVal(panel, control, &dedrift.proportional);
					break;
				case PANEL_DEDRIFT_DOUBLE_CORR:
					// double slope correction
					GetCtrlVal(panel, control, &dedrift.x2);
					break;
				case PANEL_DEDRIFT_KEEP_FREQ:
					// keep current dedrifting frequency when dedrifting is disabled
				   	GetCtrlVal(panel, control, &dedrift.keep_freq);
					break;
				case PANEL_DEDRIFT_KEEP_SLOPE:
					// keep current dedrifting slope when dedrifting is disabled
				   	GetCtrlVal(panel, control, &dedrift.keep_slope);
					break;
			}
 			break;
	}
	return 0;
}

int  CVICALLBACK CB_RecenterEnable (int panel, int control, int event, 
		 void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &recenter.enabled);
			recenter.t0 = utc;
			rollmean_zero(&rollmean_ch2);
			rollmean_zero(&rollmean_ch3);
			rollmean_zero(&rollmean_ch4);
 			break;
	}
	return 0;
}

int  CVICALLBACK CB_OnStopSlopeCancellingOnUnlocked (int panel, int control, int event, 
		 void *callbackData, int eventData1, int eventData2)
{
	int value;
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &value);
			dedrift.threshold = value ? 100.0 : 0.0;
			break;
	}
	return 0;
}

int CVICALLBACK CB_OnSlopeReference (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &dedrift.reference);
			break;
	}
	return 0;
}

int CVICALLBACK CB_SetSlope (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &dedrift.applied);
			ad9956_set_sweep_rate_w(&ad9956, dedrift.applied);
			break;
	}
	return 0;
}

int CVICALLBACK CB_InvertSlopeSign (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	int invert;
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &invert);
			dedrift.sign = invert ? -1 : +1;
			break;
	}
	return 0;
}

int CVICALLBACK CB_ResetDedriftDDS (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			// stop slope measurement and reset slope 
			dedrift.enabled = FALSE;
			SetCtrlVal(panel, PANEL_MEASURE_SLOPE, 0);
			dedrift.applied = 0.0;
			SetCtrlVal(panel, PANEL_SLOPE_APPLIED, dedrift.applied);
			// reset DDS
			ad9956_set_w(&ad9956, dedrift.fDDS, dedrift.applied);
			break;
	}
	return 0;
}

int CVICALLBACK CB_ShowLog (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	int visible;
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &visible);
			logger_panel_visible(visible);
			break;
	}
	return 0;
}

int CVICALLBACK CB_ShowError (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			logger_panel_visible(TRUE);
			SetCtrlVal(panel, control, FALSE);
			SetCtrlVal(panel, PANEL_SHOWLOG, TRUE);
			break;
	}
	return 0;
}

int CVICALLBACK CB_OnLoggingPanelEvent(int panel, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_CLOSE:
			logger_panel_visible(0);
			SetCtrlVal(MainPanel, PANEL_SHOWLOG, 0);
			break;
	}
	return 0;
}

int CVICALLBACK CB_BeatnoteSign (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			switch(control) {
				case PANEL_SIGN1:
					GetCtrlVal(panel, control, &Sign1);
					break;
				case PANEL_SIGN2:
					GetCtrlVal(panel, control, &Sign2);
					break;
				case PANEL_SIGN3:
					GetCtrlVal(panel, control, &Sign3);
					break;
			}
			break;
	}
	return 0;
}

int CVICALLBACK CB_SaveData (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			for (struct datafile *d = datafiles; d->data; d++) {
				if (d->control == control)
					GetCtrlVal(panel, control, &(d->write));
			}
			break;
	}
	return 0;
}


int CVICALLBACK CB_RecenterInterval (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &recenter.interval);
			break;
	}
	return 0;
}

int CVICALLBACK CB_RecenterChannel (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			switch (control)
			{
				case PANEL_RECENTER_LO:
					GetCtrlVal(panel, control, &recenter.lo);
					break;
				case PANEL_RECENTER_HG:
					GetCtrlVal(panel, control, &recenter.hg);
					break;
				case PANEL_RECENTER_SR:
					GetCtrlVal(panel, control, &recenter.sr);
					break;
			}
			break;
	}
	return 0;
}

int CVICALLBACK CB_SrDatalogger (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &datalogger.enabled);
			break;
	}
	return 0;
}

int CVICALLBACK CB_DedriftDDSFreq (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &dedrift.fDDS);
			ad9956_set_w(&ad9956, dedrift.fDDS, dedrift.applied);
			break;
	}
	return 0;
}


//
// N estimate 
//

static void estimateN (void)
{
	double nu, fbeat, frep, N;
	int sign;
	
	GetCtrlVal(EstimateNPanel, ESTIMATEN_FREQUENCY, &nu);
	GetCtrlVal(EstimateNPanel, ESTIMATEN_FREP, &frep);
	GetCtrlVal(EstimateNPanel, ESTIMATEN_FBEAT, &fbeat);
	GetCtrlVal(EstimateNPanel, ESTIMATEN_SIGN, &sign);
		
	N = (nu * 1.0e12 - sign * fbeat) / frep;
	
	SetCtrlVal(EstimateNPanel, ESTIMATEN_N, N);
}

int CVICALLBACK cb_onEstimateN (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	int visible;
	
	switch (event)
	{
		case EVENT_COMMIT:
			// reset N estimate
			SetCtrlVal(EstimateNPanel, ESTIMATEN_N, 0.0);
			// set current frep
			SetCtrlVal(EstimateNPanel, ESTIMATEN_FREP, 250e6 + Math1);
			switch (control) {
				case PANEL_ESTIMATE_N2:
					// expected frequency
					SetCtrlVal(EstimateNPanel, ESTIMATEN_FREQUENCY, HG_FREQUENCY);
					SetCtrlVal(EstimateNPanel, ESTIMATEN_WAVELENGTH, HG_WAVELENGTH);
					// sign
					SetCtrlVal(EstimateNPanel, ESTIMATEN_SIGN, (int)Sign2);
					// f_DDS
					SetCtrlVal(EstimateNPanel, ESTIMATEN_FDDS, ad9912.frequency[2]);
					// f_counter
					SetCtrlVal(EstimateNPanel, ESTIMATEN_FDDS, Ch2);
					// f_beat
					SetCtrlVal(EstimateNPanel, ESTIMATEN_FBEAT, ad9912.frequency[2] - Ch2);
					
					SetPanelAttribute(EstimateNPanel, ATTR_TITLE, "Estimate N_Hg");
					SetPanelAttribute(EstimateNPanel, ATTR_CALLBACK_DATA, INT_TO_PTR(HG));
					break;
				case PANEL_ESTIMATE_N3:
					// expected frequency
					SetCtrlVal(EstimateNPanel, ESTIMATEN_FREQUENCY, SR_FREQUENCY);
					SetCtrlVal(EstimateNPanel, ESTIMATEN_WAVELENGTH, SR_WAVELENGTH);
					// sign
					SetCtrlVal(EstimateNPanel, ESTIMATEN_SIGN, (int)Sign3);
					// f_DDS
					SetCtrlVal(EstimateNPanel, ESTIMATEN_FDDS, ad9912.frequency[3]);
					// f_counter
					SetCtrlVal(EstimateNPanel, ESTIMATEN_FDDS, Ch3);
					// f_beat
					SetCtrlVal(EstimateNPanel, ESTIMATEN_FBEAT, ad9912.frequency[3] - Ch3);

					SetPanelAttribute(EstimateNPanel, ATTR_TITLE, "Estimate N_Sr");
					SetPanelAttribute(EstimateNPanel, ATTR_CALLBACK_DATA, INT_TO_PTR(SR));
					break;
			}
			
			// display dialog
			GetPanelAttribute(EstimateNPanel, ATTR_VISIBLE , &visible);
			if (! visible)
				DisplayPanel(EstimateNPanel);
			
			// compute
			estimateN();
			break;
	}
	return 0;
}

int CVICALLBACK cb_onEstimateNWaveleght (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	double wavelenght, frequency;
	
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &wavelenght);
			frequency = SPEED_OF_LIGHT / (wavelenght * 1.0e-9) / 1.0e12;
			SetCtrlVal(panel, ESTIMATEN_FREQUENCY, frequency);
			estimateN();
			break;
	}
	return 0;
}

int CVICALLBACK cb_onEstimateNFrequency (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	double wavelenght, frequency;
	
	switch (event)
	{
		case EVENT_COMMIT:
			GetCtrlVal(panel, control, &frequency);
			wavelenght = SPEED_OF_LIGHT / (frequency * 1.0e12) / 1.0e-9;
			SetCtrlVal(panel, ESTIMATEN_WAVELENGTH, wavelenght);
			estimateN();
			break;
	}
	return 0;
}

int CVICALLBACK cb_onEstimateNChange (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	switch (event)
	{
		case EVENT_COMMIT:
			estimateN();
			break;
	}
	return 0;
}

int CVICALLBACK cb_onEstimateNClose (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	int visible;
	
	switch (event)
	{
		case EVENT_COMMIT:
			GetPanelAttribute(panel, ATTR_VISIBLE, &visible);
			if (visible)
				HidePanel(panel);
			break;
	}
	return 0;
}

int CVICALLBACK cb_onEstimateNSet (int panel, int control, int event,
		void *callbackData, int eventData1, int eventData2)
{
	void *v;
	double n;
	int estimate = 0;
	
	switch (event)
	{
		case EVENT_COMMIT:
			GetPanelAttribute(panel, ATTR_CALLBACK_DATA, &v);
			estimate = PTR_TO_INT(v);
			switch (estimate) {
				case HG:
					GetCtrlVal(panel, ESTIMATEN_N, &n);
					N2 = round(n);
					SetCtrlVal(MainPanel, PANEL_N2, N2);
					break;
				case SR:
					GetCtrlVal(panel, ESTIMATEN_N, &n);
					N3 = round(n);
					SetCtrlVal(MainPanel, PANEL_N3, N3);
					break;
			}
			HidePanel(panel);
			break;
	}
	return 0;
}