pulsesequence()
{
double pd, seqtime;
double mintDELTA,ted1,ted2,gf;
double restol, resto_local;
init_mri(); /****needed ****/
restol=getval("restol"); //local frequency offset
roff=getval("roff"); //receiver offset
init_rf(&p1_rf,p1pat,p1,flip1,rof1,rof2); /* hard pulse */
calc_rf(&p1_rf,"tpwr1","tpwr1f");
init_rf(&p2_rf,p2pat,p2,flip2,rof1,rof2); /* hard pulse */
calc_rf(&p2_rf,"tpwr2","tpwr2f");
gf=1.0;
if(diff[0] == 'n') gf=0;
int vph180 = v2; /* Phase of 180 pulse */
mintDELTA = tdelta + trise + rof1 + p2 + rof2;
if(tDELTA <= mintDELTA) {
abort_message("%s: tDELTA too short. Min tDELTA = %f ms",seqfil,mintDELTA*1e3);
}
ted1 = tDELTA - tdelta + trise + p2 + rof1 + rof2;
te = p1/2 + rof2 + tdelta + trise + ted1 + rof1 + p2/2; /* first half-te */
ted2 = te - p2/2 - rof2 - tdelta - trise;
if((ted1 <= 0)||(ted2 <= 0) ) {
abort_message("%s: tDELTA too short. Min tDELTA = %f ms",seqfil,mintDELTA*1e3);
}
te = te*2.0;
putvalue("te",te);
seqtime = at+(p1/2.0)+rof1+te;
pd = tr - seqtime; /* predelay based on tr */
if (pd <= 0.0) {
abort_message("%s: Requested tr too short. Min tr = %f ms",seqfil,seqtime*1e3);
}
resto_local=resto-restol;
status(A);
rotate();
delay(pd);
xgate(ticks);
/* --- observe period --- */
obsoffset(resto_local);
obspower(p1_rf.powerCoarse);
obspwrf(p1_rf.powerFine);
shapedpulse(p1pat,p1,oph,rof1,rof2);
obl_gradient(0,0,gdiff*gf); /* x,y,z gradients selected via orient */
delay(tdelta);
zero_all_gradients();
delay(trise);
delay(ted1);
obspower(p2_rf.powerCoarse);
obspwrf(p2_rf.powerFine);
settable(t2,2,ph180); /* initialize phase tables and variables */
getelem(t2,ct,v6); /* 180 deg pulse phase alternates +/- 90 off the rcvr */
add(oph,v6,vph180); /* oph=zero */
shapedpulse(p2pat,p2,vph180,rof1,rof2);
obl_gradient(0,0,gdiff); /* x,y,z gradients selected via orient */
delay(tdelta);
zero_all_gradients();
delay(trise);
delay(ted2);
startacq(alfa);
acquire(np,1.0/sw);
endacq();
}
pulsesequence()
{
/*******************************************************/
/* Internal variable declarations */
/*******************************************************/
double predelay;
double agss,grate,gssint, gssrint;
double t_after, acq_delay, min_tr;
double t_rampslice, t_plateau_sr, t_plateau_min, t_ramp_sr;
double slice_offset,f_offset;
double pss0;
char slice_select[MAXSTR];
initparms_sis(); /* Sets default state of receiver to ON */
/*- will be obsolete on future VNMR versions */
/***************************/
/* initialize variables */
/***************************/
gssf = 1.0; /* slice select fractional refocus */
predelay = PREDELAY; /* define predelay [s] */
acq_delay = ACQ_DELAY; /* time delay between end of refocus and acq */
slice_offset = 0.0; /* force slice offset to 0.0 [cm] */
t_rampslice = 0.0; /* slice select ramp time */
t_ramp_sr = 0.0; /* slice refocusing ramp time */
t_plateau_min = 0.0005; /* min time slice refocusing plateau */
t_plateau_sr =0.0; /* slice refocusing plateau time*/
f_offset=getval("resto");
agss = fabs(gss); /* absolute slice select gradient */
gssr = gmax; /* maximum slice refocusing gradient */
grate = trise/gmax; /* define gradient slew rate [s*cm/g]
trise = gradient rise time
gmax = maximum gradient strength [G/cm] */
ticks = IGNORE_TRIGGER; /* ignore trigger pulses */
/***************************/
/* Get parameter */
/***************************/
at = getval("at");
pss0 = getval("pss0");
getstr("slice_select",slice_select); /* slice select flag
[y] = ON, [n] = OFF */
/*******************************************************/
/* Slice Select gradient area */
/*******************************************************/
t_rampslice = grate * agss;
gssint = (agss*p1/2.0) + (agss*t_rampslice/2.0);
gssrint=gssint;
/*******************************************************
* Calculate slice refocussing gradient *
*******************************************************/
t_plateau_sr = (gssint / gssr) - trise;
if (t_plateau_sr <= 0.0) /* traingular gradients */
{
t_plateau_sr = 0.0;
gssr = sqrt(gssint / grate);
}
t_ramp_sr = gssr * grate; /* ramp time for refocusing gradient*/
gssrint = (gssr * t_plateau_sr) + (t_ramp_sr * gssr);
/***************************************************************************
* timing calculation *
***************************************************************************/
if (slice_select[0] == 'y')
{
t_after = tr - (predelay + p1 + t_plateau_sr + at + acq_delay + 2* (t_rampslice + t_ramp_sr));
min_tr = predelay + p1 + t_plateau_sr + at + acq_delay + 2* (t_rampslice + t_ramp_sr);
}
else
{
t_after = tr - (predelay + p1 + at + acq_delay );
min_tr = predelay + p1 + at + acq_delay ;
}
if (t_after < 0.0)
{
abort_message("Requested repetition time (TR) too short. Min tr = %.f[ms]\n",min_tr*1000);
}
/******************************************************/
/* */
/* S T A R T */
/* P U L S E S E Q U E N C E */
/* */
/******************************************************/
obspower(tpwr1); /* set tranmitter power */
/***************************************************************************
* Predelay *
***************************************************************************/
obsoffset(f_offset); /* set transmitter offset */
delay(predelay);
xgate(ticks); /* set gating */
if (slice_select[0] == 'y')
{
/***************************************************************************
* Slice select gradient & RF pulse *
***************************************************************************/
obl_gradient(0.0,0.0,gss); /* slice select gradient */
delay(t_rampslice); /* delay - time to ramp up gradient */
shaped_pulse(p1pat,p1,oph,rof1,rof1);
zero_all_gradients(); /* force all gradients back to 0 [G/cm] */
delay(t_rampslice); /* time to ramp down gradient */
/***************************************************************************
* Slice refocus gradient *
***************************************************************************/
obl_gradient(0.0,0.0,-gssr); /* slice refocus gradient */
delay(t_ramp_sr+t_plateau_sr); /* ramp up of refocus gradient */
zero_all_gradients(); /* force refocus gradient back to 0 [G/cm] */
delay(t_ramp_sr); /* time to ramp down gradient */
}
else
{
shaped_pulse(p1pat,p1,oph,rof1,rof1);
}
/***************************************************************************
* Pre-acquire delay *
***************************************************************************/
delay(acq_delay);
/***************************************************************************
* Acquire echo *
***************************************************************************/
startacq(alfa);
acquire(np,1.0/sw); /* acquire FID */
endacq();
delay(t_after); /* time padding to fill TR */
/******************************************************/
/* */
/* E N D */
/* P U L S E S E Q U E N C E */
/* */
/******************************************************/
}
