/* gNhsqc.c
HSQC gradient sensitivity enhanced version for N15, with options for
TROSY on N15/H1 and for T1, T1rho, and T2 relaxation measurements of the
N15 nuclei. Coherence transfer gradients may be z or magic-angle (using
triax probe).
Standard features include optional 13C sech/tanh pulse on CO and Ca to
refocus 13C coupling during t1; 1D checks of N15 and H1 pulse times using
calN and calH; one lobe sinc pulse to put H2O back along z (the sinc
one-lobe is significantly more selective than gaussian, square, or seduce
90 pulses); preservation of H20 along z during t1 and the relaxation
delays; option of obtaining spectrum of only NH2 groups; 2H decoupling
option for partially-deuterated (ie NHD) groups.
pulse sequence: Kay, Keifer and Saarinen, JACS, 114, 10663 (1992)
sech/tanh pulse: Silver, Joseph and Hoult, JMR, 59, 347 (1984)
Bendall, JMR, A116, 46 (1995)
relaxation times: Kay et al, JMR, 97, 359 (1992)
Farrow et al, Biochemistry, 33, 5984 (1994)
TROSY: Weigelt, JACS, 120, 10778 (1998)
Written by MRB, December 1997, starting with ghn_co from BioPack.
Revised and improved to a standard format by MRB, BKJ and GG for the
BioPack, January 1998, so as to include calculation of the above
standard features within the pulse sequence code and associated macro.
Minor additions during 98, TROSY added Dec 98. (Version Dec 1998).
Modified the amplitude of the flipback pulse(s) (pwHs) to permit user adjustment around
theoretical value (tpwrs). If tpwrsf < 4095.0 the value of tpwrs is increased 6db and
values of tpwrsf of 2048 or so should give equivalent amplitude. In cases of severe
radiation damping( which happens during pwHs) the needed flip angle may be much less than
90 degrees, so tpwrsf should be lowered to a value to minimize the observed H2O signal in
single-scan experiments (with ssfilter='n').(GG jan01)
*************************************************************************************
Changes of original gNhsqc pulse sequence made at NMRFAM to improve water suppression
(M.T. and K.H.)
*************************************************************************************
In order to improve water suppression in systems with high-Q probes, such as cold
probes, have modified the gNhsqc pulse sequence and written macros to automatically
calibrate the flipback pulses that are used. Before running this experiment, it is
always recommended to run the calibrating macro to obtain the best water
suppression.
For information about the original sequence, gNhsqc, type man('gNhsqc')
Changes made at NMRFAM to the original sequence, gNhsqc. May-August 2003.
(1) Changes to the "regular" sensitivity enhanced 15N HSQC experiment:
- changed the phase of the first 90 flipback pulse from -X to X;
the phase of the flipback pulse is changed such that the water
magnetization is flipped back to +Z at the end of the first INEPT
sequence
- added a 2nd 180 flipback pulse right after the 180 1H hard pulse
during 15N evolution time; the water magnetization is flipped to -Z
by the hard 180 during the 15N evolution time, the 2nd 180 flipback
pulse is then required to flip the water magnetization back to +Z.
By making these two changes, the water magnetization is kept along +Z
throughout 15N evolution time.
(2) Added small angle phase correction to all flipback pulses used in the pulse
sequence
(3) A new parameter "gstab1" has been created to control the lenght of the
recovery delay following the first coherence selection gradient (gt1).
In systems with high-Q probes, such as cold probes, it takes longer to
recover from Eddy currents induced in the coils by pulsed gradients.
This recovery delay seems to affect water suppression, with longer
delays giving better water suppression in a two dimensional experiment
(but it may not have a clear effect in a 1D spectrum). Values above or
equal to 200us (gstab=0.0002) are strongly recomended.
(4) Macro "fbcal" written to calibrate flipback pulses. Two parameters are
calibrated for each flipback pulse to optimize water suppression :
1)fine power needs to be adjusted for each pulse as the flipback
angle is affected by radiation damping
2)a small angle phase correction is applied to most flipback pulses to
optimize water suppression for two reasons:
- to compensate for the small phase error that is introduced
in the flipback pulse by the fine power attenuator (point 1
above)
- to compensate for radiation damping that induces a rotation
of the water magnetization at the end of INEPT sequences.
The phase of flipback pulses at the end of INEPT sequences
can be adjusted to take this rotation into account and
optimize water suppression
HOW TO RUN THIS EXPERIMENT AND USE the "fbcal" MACRO
Before running this experiment, it is always recommended to run the "fbcal"
macro to calibrate the flipback pulses.
1- call up the modified 15N HSQC sequence by typing the name of the sequence
"gNhsqc_2fb" in the vnmr command line
2- select the type of experiment that you want to perform (flags: TROSY,
NH2only, T1, T1rho, T2)
3- set up all the important parameters that will affect the flipback
calibration, that is:
+ tpwr
+ pw
+ compH
+ pwHs, lenght of the flipback pulse in microseconds
+ gt0, lenght of the gradient pulse during the first INEPT
transfer; this parameter is not usually changed by the
user, but, if it is it will affect the small angle
phase correction needed for the flipback pulse that
follows the INEPT and thus it needs to be set before
the calibration macro "fbcal" is run
4- call up the "fbcal" macro by typing its name in the vnmr command line
+ the macro will read the parameters from the experiment and
save them in a temporary file
+ the macro will then load other sequences to calibrate the fine
power and phase of the flipback pulses used, this is done
automatically through several iterations minimizing the water
peak (no further input by the user is needed)
+ at the end of the calibration the macro will recall the initial
15N HSQC pulse sequence with all the parameters and update the
flipback parameters that it just calibrated
+ the macro will then adquire a 1D spectrum of the 15N HSQC using
the paramters it just calibrated with ss=4 nt=16 and using
autogain (gain='n')
+ this whole calibration process takes about 2 minutes, it's
fully automated and is recommended to obtain the best water
suppression for this sequence
NOTE:
- If any of the important paramters listed above (tpwr,pw,compH,pwHs,gt0)
or the type of experiment to run is changed, the flipback calibration
should be repeated.
- If, for any reason, the macro "fbcal" fails to work, the initial 15N HSQC
pulse sequence with all the paramteres set by the user can be recalled
by typing "recover" in the vnmr command line
PARAMETERS CALIBRATED BY "fbcal"
This pulse sequence, like the original one, allows one to perform
different experiments:
- HSQC (regular and TROSY version)
- NH2only
- T1, T1rho and T2 measuraments
each of these experiments may use different flipback pulses that require
a specific calibration. This specific calibration is performed
automatically by "fbcal".
- phincr90 and tpwrsf90 : small angle phase correction and fine power
attenuation level for the flipback pulse that
follows the first INEPT transfer. All possible
experiments have this flipback pulse and these
2 parameters. For NH2only and relaxation
measurements (T1, T1rho and T2) experiments,
this is the only flipback pulse used.
Note that the values of phincr90 and tpwrsf90
found by "fbcal" may be different for different
experiments, because the flipback pulse is used
in different ways (and calibrated accordingly).
- tpwrsf180 : fine power attenuation level for the 2nd 180 flipback pulse
used only in the regular HSQC experiment (all flags = 'n').
No small angle phase correction required for this pulse)
- phincr270 and tpwrsf270 : small angle phase correction and fine power
attenuation level for the 2nd 90 flipback pulse
that is used only when the TROSY experiment is
run (TROSY='y').
FILES AND PULSE SEQUENCES USED BY THIS PACKAGE
Several pulse sequence, parameter, macro, manual and template files are
used by this package.
Pulsesequence files (psglib directory) :
gNhsqc_2fb.c - modified 15N HSQC pulse sequence
mt_flipback_cal.c - pulse sequence to calibrate flipback pulses
immediately following or preceeding a hard pulse
(90 or 180 degrees) and flipback pulses following
INEPT transfers
Paramter files (parlib directory):
gNhsqc_2fb.par - standard parameters for gNhsqc_2fb experiment
INEPT_flipback_cal.par - standard parameters for INEPT_flipback_cal
experiment
mt_flipback_cal.par - standard parameters for mt_flipback_cal experiment
Macro files (maclib directory):
gNhsqc_2fb - macro to load gNhsqc_2fb experiment
INEPT_flipback_cal - macro to load INEPT_flipback_cal experiment
mt_flipback_cal - macro to load mt_flipback_cal experiment
fbcal - main macro that calibrates the flipback pulses used by the
gNhsqc_2fb pulse sequence
find_tpwrsf_phincr - macro called by fbcal during calibration
findbestone - macro called by fbcal during calibration
recover - macro that loads the gNhsqc_2fb sequence with the initial
paramters that can be used if the calibration is stopped
before it's finished
Manual files (manual directory):
gNhsqc_2fb - file with instructions on how to set up this sequence
for optimal water suppression
Template files (templates/dg/gNhsqc_2fb directory):
dg.* - a series of files that control the user-friendly menus for
the gNhsqc_2fb pulse sequences
*************************************************************************************
If you have any problem please contact Klaas or me : hallenga@nmrfam.wisc.edu
tonelli@nmrfam.wisc.edu
*************************************************************************************
CHOICE OF DECOUPLING AND 2D MODES
Set dm = 'nnn', dmm = 'ccc'
Set dm2 = 'nny', dmm2 = 'ccg' (or 'ccw', or 'ccp') for N15 decoupling.
Set dm3='nyn', dmm2='cwc' for 2H decoupling using 4th channel
Must set phase = 1,2 for States-TPPI acquisition in t1 [N15].
The flag f1180 should be set to 'y' if t1 is to be started at halfdwell
time. This will give -90, 180 phasing in f1. If it is set to 'n' the
phasing should be 0,0 and will still give a perfect baseline. Thus,
set f1180='n' for (0,0) in N15. f1180='y' is ignored if ni=0.
DETAILED INSTRUCTIONS FOR USE OF gNhsqc
1. Obtain a printout of the Philosopy behind the BioPack development,
and General Instructions using the macro:
"printon man('BioPack') printoff".
These Detailed Instructions for gNhsqc may be printed using:
"printon man('gNhsqc') printoff".
2. Apply the setup macro "gNhsqc". This loads the relevant parameter set
and also sets ni=0 and phase=1 ready for a 1D spectral check.
3. Centre H1 frequency on H2O (4.7ppm), C13 frequency on 100ppm, and N15
frequency on the amide region (120 ppm).
4. CALIBRATION OF pw AND pwN:
calN and calH are multipliers of the first N15 and H1 90 degree pulses
in the sequence. They can be used to calibrate the pulses using a 1D
spectrum. Setting either calN or calH = 2.0 should give a S/N null (or
small dispersion signals) corresponding to the pulses being set at 180
degrees. Adjust pwN or pw, respectively, until this occurs. An array
of calH or calN = 1.8, 2.0, 2.2 is also convenient to judge the null at
2.0. calN and calH are automatically reset to 1 for 2D spectra if you
forget to do so. (Note that compH and compN can be calibrated using
calH and calN in an analogous way to compC as in point 6, gChsqc
manual).
5. CALIBRATION OF dof2:
Set ni=ni2=0 and phase=phase2=1 and obtain a well=phased absorption mod
1D spectrum. Set d2=0.0001 and phase=1,2, sum the two resulting spectra
and display in exp5 with a 90 degree phase shift:
clradd select(1) spadd select(2) spadd jexp5 full rp=rp+90 ds
dof2 will be in the middle of the NH region when the signals between
7.4 and 9ppm in the 1H spectrum are roughly balanced between +ve and
-ve signals. Note that the same method with d2=0 should give a zero
spectrum. Don't forget to reset d2=0 when you have finished.
6. Splitting of resonances in the N15 dimension by C13 coupling in C13
enriched samples can be removed by setting C13refoc='y'.
7. H2O preservation is achieved according to Kay et al, except that a sinc
one-lobe selective pulse is used to put H2O back along z. This is much
more selective than a hard, Seduce1, or gaussian pulse. H2O is cycled
back to z as much as possible during t1, and during the relaxation
delays for the following relaxation time measurements.
8. T1 MEASUREMENTS OF NH GROUPS:
Implemented automatically by setting the flag T1='y'. An array of 1D
spectra is obtained by arraying the relaxation time parameter,
relaxT, to a multiple of 10 milliseconds. relaxT corresponds
exactly to the relaxation time of the N15 spins. The method uses 180
degree H1 pulses every 5ms during relaxT as according to Kay et al.
An alternative method using waltz decoupling was tested and discarded.
It gave exactly the same results using alphalytic protease, but has
the comparative disadvantage of delivering more H1 RF, so more heating.
2D spectra should be acquired in a separate run for each of the desired
values of relaxT. (maxrelaxT as in point 10 is not used when T1='y'.)
10. T1rho MEASUREMENTS OF NH GROUPS:
Implemented by setting the flag T1rho='y' and arraying relaxT as above.
relaxT corresponds exactly to the relaxation time of the N15 spins.
Spin lock power is limited to 1.5 kHz for a 600 Mhz spectrometer as
this delivers about the same sample heating as the T2 method below.
Increasing this RF (by changing the number 1500 in the DECLARE AND LOAD
VARIABLES section of gNhsqc.c) causes substantial sample or coil heating
as indicated by deterioration of the lock signal). Care should be taken
for relaxT times greater than 0.25 seconds, and times greater than
0.5 seconds are automatically aborted. Gives very similar results
to the T2 method as determined using alphalytic protease. A dummy
period of spinlock RF is delivered at the beginning of each pulse
sequence to ensure constant average sample heating - the code
determines this from the maximum relaxT you have set in your array of
relaxT. The spectrum at relaxT=0 may be erroneous because of insufficient
dephasing of unlocked spins.
2D spectra should be acquired in a separate run for each of the desired
values of relaxT. If T1rho measurements are to be made in different
experiments with different relaxTs as for 2D, including arrays of
relaxT's, set the parameter maxrelaxT to the maximum relaxT you have
set in all experiments - this will ensure constant average sample
heating in all experiments. maxrelaxT does not need to be set for a
single array in a single exp.
11. T2 MEASUREMENTS OF NH GROUPS:
Implemented by setting the flag T2='y' and arraying relaxT as above.
relaxT corresponds exactly to the relaxation time of the N15 spins.
As for T1rho, care should be taken for relaxT times greater than 0.25
seconds, and times greater than 0.5 seconds are automatically aborted.
The method is according to Kay et al, with N15 180's every 625 us, and
H1 180's every 10 ms. 625us was used instead of approx 500us used by
Kay et al to reduce sample heating. An alternative method using the
same no. of N15 and H1 pulses for all relaxT times (by decreasing the
625us delays to obtain short relaxT) to test whether large nos. of
pulses decreases S/N because of pulse imperfection, gave exactly
equivalent results for alphalytic protease, and was discarded. Another
alternative, with waltz H1 decoupling and a single N15 180 at the middle
of relaxT (credited to Wagner et al by Kay et al), gave substantially
shorter apparent T2 times, and was discarded. A dummy period of N15
180's is delivered at the beginning of each pulse sequence to ensure
constant average sample heating.
2D spectra should be acquired in separate runs with maxrelaxT
set as for T1rho='y' in point 10.
12. NH2 GROUPS:
A spectrum of NH2 groups, with NH groups cancelled, can be obtained
with flag NH2only='y'. This utilises a 1/2J (J=94Hz) period of NH
J-coupling evolution added to t1 which cancels NH resonances and
inverts NH2 resonances (normal INEPT behaviour). A 180 degree phase
shift is added to a N15 90 pulse to provide positive NH2 signals.
The NH2 resonances will be smaller (say 80%) than when NH2only='n'.
13. RELAXATION MEASUREMENTS OF NH2 GROUPS:
NH2 resonances are supressed for the methods described in points 9-11.
To obtain relaxation times of NH2 groups, set the flag NH2only='y' and
proceed as for points 9-11. In these cases the 1/2J delays described
in points 8 and 12 are changed to 1/4J delays by the pulse sequence
code. Although NH groups are completely cancelled in point 12, when
measuring relaxation times NH groups appear at 50% intensity.
14. The coherence-transfer gradients using power levels
gzlvl1 and gzlvl2 may be either z or magic-angle gradients. For the
latter, a proper /vnmr/imaging/gradtable entry must be present and
syscoil must contain the value of this entry (name of gradtable). The
amplitude of the gzlvl1 and gzlvl2 should be lower than for a z axis
probe to have the x and y gradient levels within the 32k range. For
any value, a dps display (using power display) shows the x,y and z
dac values. These must be <=32k.
15. 1/4J DELAY TIMES:
These are are determined from the NH coupling constant, JNH, listed in
dg for possible change by the user. lambda is the 1/4J time for H1 NH
coupling evolution, tNH is the 1/4J time for N15 NH coupling evolution.
lambda is usually set a little lower than the theoretical time to
minimise relaxation, but tNH should be as close to the theoretical time
as possible.
16. TROSY and COUPLED 2D SPECTRA:
Set TROSY='y' and dm2='nnn' for a TROSY spectrum of the bottom right
peak of the 2D coupled quartet (high-field H1, low-field N15). For
comparison, TROSY='n' and dm2='nnn' gives a 2D spectrum coupled in
both dimensions. The TROSY spectrum retains the N15 magnetization as
well as the H1 magnetization and so gives a little more than 50% S/N
than decoupled HSQC for a small peptide. For TROSY, H2O flipback is
maintained throughout t1 and t2 using two sinc one-lobe pulses (H2O is
inverted for half of t1 for normal HSQC, ie TROSY='n' as described in
point 7). To select any of the other three peaks of the 2D coupled
quartet, in a clockwise direction from bottom right, change t4/t10
from x/y to x/-y to -x/-y to -x/y. NOTE, the Varian phases are of
opposite sense to those in the Weigelt paper, ie swap y and -y. The
same phases as written by Weigelt also work provided the +/- gzlvl1
signs for phase=1,2 are swapped to -/+, and the phase of one of the
first two H1 90 degree pulses is swapped to ensure that the N15
magnetization adds rather than subtracts. The phase list used for
this sequence code is yet another equivalent which permits the least
change from the normal SE train in the BioPack sequences.
Relaxation time measurements have not yet been implemented for TROSY
spectra (requires customer demand !).
17. Radiation Damping:
At fields 600MHz and higher with high-Q probes, radiation damping is a
factor to be considered. Its primary effect is in the flipback pulse
calibration. Radiation damping causes a rotation back to the +Z axis
even without a flipback pulse. Hence, the pwHs pulse often needs to
be reduced in its flip-angle. This can be accomplished by using the
parameter tpwrsf. If this value is less than 4095.0 the value of tpwrs
(calculated in the psg code) is increased by 6dB, thereby permitting
the value of tpwrsf to be optimized to obtain minimum H2O in the
spectrum. The value of tpwrsf is typically lower than 2048 (half-maximum
to compensate for the extra 6dB in tpwrs).
*/
#include <standard.h>
static int /* T is for TROSY='y', phx etc also enable TROSY phase changes */
phx[1]={0}, phy[1]={1}, ph_x[1]={2},
phi3[2] = {0,2},
phi9[8] = {0,0,1,1,2,2,3,3},
rec[4] = {0,2,2,0}, recT[2] = {1,3};
static double d2_init=0.0, relaxTmax;
pulsesequence()
{
/* DECLARE AND LOAD VARIABLES */
char f1180[MAXSTR], /* Flag to start t1 @ halfdwell */
mag_flg[MAXSTR], /* magic-angle coherence transfer gradients */
C13refoc[MAXSTR], /* C13 sech/tanh pulse in middle of t1*/
NH2only[MAXSTR], /* spectrum of only NH2 groups */
T1[MAXSTR], /* insert T1 relaxation delay */
T1rho[MAXSTR], /* insert T1rho relaxation delay */
T2[MAXSTR], /* insert T2 relaxation delay */
TROSY[MAXSTR]; /* do TROSY on N15 and H1 */
int icosel, /* used to get n and p type */
t1_counter, /* used for states tppi in t1 */
rTnum, /* number of relaxation times, relaxT */
rTcounter; /* to obtain maximum relaxT, ie relaxTmax */
double
tau1, /* t1 delay */
lambda = 0.91/(4.0*getval("JNH")), /* 1/4J H1 evolution delay */
tNH = 1.0/(4.0*getval("JNH")), /* 1/4J N15 evolution delay */
relaxT = getval("relaxT"), /* total relaxation time */
rTarray[1000], /* to obtain maximum relaxT, ie relaxTmax */
maxrelaxT = getval("maxrelaxT"), /* maximum relaxT in all exps */
ncyc, /* number of pulsed cycles in relaxT */
/* the sech/tanh pulse is automatically calculated by the macro "proteincal", */ /* and is called directly from your shapelib. */
pwClvl = getval("pwClvl"), /* coarse power for C13 pulse */
pwC = getval("pwC"), /* C13 90 degree pulse length at pwClvl */
rf0, /* maximum fine power when using pwC pulses */
rfst, /* fine power for the stCall pulse */
compH = getval("compH"), /* adjustment for H1 amplifier compression */
compN = getval("compN"), /* adjustment for N15 amplifier compression */
compC = getval("compC"), /* adjustment for C13 amplifier compression */
calH = getval("calH"), /* multiplier on a pw pulse for H1 calibration */
pwHs = getval("pwHs"), /* H1 90 degree pulse length at tpwrs */
tpwrs, /* power for the pwHs ("H2Osinc") pulse */
tpwrsf = getval("tpwrsf"),
tpwrsf90 = getval("tpwrsf90"),
phincr90 = getval("phincr90"),
tpwrsf270 = getval("tpwrsf270"),
phincr270 = getval("phincr270"),
tpwrs180,
tpwrsf180 = getval("tpwrsf180"),
pwNlvl = getval("pwNlvl"), /* power for N15 pulses */
pwN = getval("pwN"), /* N15 90 degree pulse length at pwNlvl */
calN = getval("calN"), /* multiplier on a pwN pulse for calibration */
slNlvl, /* power for N15 spin lock */
slNrf = 1500.0, /* RF field in Hz for N15 spin lock at 600 MHz */
sw1 = getval("sw1"),
gt1 = getval("gt1"), /* coherence pathway gradients */
gt2 = getval("gt2"), /* coherence pathway gradients */
gzcal = getval("gzcal"), /* dac to G/cm conversion */
gzlvl1 = getval("gzlvl1"),
gzlvl2 = getval("gzlvl2"),
gt0 = getval("gt0"), /* other gradients */
gt3 = getval("gt3"),
gt4 = getval("gt4"),
gt5 = getval("gt5"),
gstab = getval("gstab"),
gstab1 = getval("gstab1"),
gzlvl0 = getval("gzlvl0"),
gzlvl3 = getval("gzlvl3"),
gzlvl4 = getval("gzlvl4"),
gzlvl5 = getval("gzlvl5");
getstr("f1180",f1180);
getstr("mag_flg",mag_flg);
getstr("C13refoc",C13refoc);
getstr("NH2only",NH2only);
getstr("T1",T1);
getstr("T1rho",T1rho);
getstr("T2",T2);
getstr("TROSY",TROSY);
/* LOAD PHASE TABLE */
settable(t3,2,phi3);
settable(t4,1,phx);
if (TROSY[A]=='y')
{settable(t1,1,ph_x);
settable(t9,1,phx);
settable(t10,1,phy);
settable(t11,1,phx);
settable(t12,2,recT);}
else
{settable(t1,1,phx);
settable(t9,8,phi9);
settable(t10,1,phx);
settable(t11,1,phy);
settable(t12,4,rec);}
/* set phase of 90 flipback pulse that follows the first INEPT transfer */
if ((TROSY[A]=='y') || (NH2only[A]=='y'))
settable(t2,1,ph_x);
else
settable(t2,1,phx);
/* INITIALIZE VARIABLES */
/* maximum fine power for pwC pulses (and initialize rfst) */
rf0 = 4095.0; rfst=0.0;
/* 180 degree adiabatic C13 pulse from 0 to 200 ppm */
if (C13refoc[A]=='y')
{rfst = (compC*4095.0*pwC*4000.0*sqrt((30.0*sfrq/600.0+7.0)/0.35));
rfst = (int) (rfst + 0.5);
if ( 1.0/(4000.0*sqrt((30.0*sfrq/600.0+7.0)/0.35)) < pwC )
{ text_error( " Not enough C13 RF. pwC must be %f usec or less.\n",
(1.0e6/(4000.0*sqrt((30.0*sfrq/600.0+7.0)/0.35))) ); abort(1); }}
/* selective H20 one-lobe sinc pulse */
tpwrs = tpwr - 20.0*log10(pwHs/(compH*pw*1.69)); /*needs 1.69 times more*/
tpwrs = (int) (tpwrs); /*power than a square pulse */
tpwrs180 = (int) (tpwrs+6.0); /*double power for 180 flipback pulse */
/* power level for N15 spinlock (90 degree pulse length calculated first) */
slNlvl = 1/(4.0*slNrf*sfrq/600.0) ;
slNlvl = pwNlvl - 20.0*log10(slNlvl/(pwN*compN));
slNlvl = (int) (slNlvl + 0.5);
/* use 1/8J times for relaxation measurements of NH2 groups */
if ( (NH2only[A]=='y') && ((T1[A]=='y') || (T1rho[A]=='y') || (T2[A]=='y')) )
{ tNH = tNH/2.0; }
/* reset calH and calN for 2D if inadvertently left at 2.0 */
if (ni>1.0) {calH=1.0; calN=1.0;}
/* make small angle phase correction always positive */
if (phincr90<0.0) phincr90=phincr90+360.0;
if (phincr270<0.0) phincr270=phincr270+360.0;
/* CHECK VALIDITY OF PARAMETER RANGES */
if ((TROSY[A]=='y') && (gt1 < -gstab1 +pwHs +5.0e-5 +2.0*POWER_DELAY))
{ text_error( " gt1 is too small. Make gt1 equal to %f or more.\n",
(-gstab1 +pwHs +5.0e-5 +2.0*POWER_DELAY) ); abort(1); }
if((dm[A] == 'y' || dm[B] == 'y' || dm[C] == 'y' ))
{ text_error("incorrect dec1 decoupler flags! Should be 'nnn' "); abort(1); }
if((dm2[A] == 'y' || dm2[B] == 'y'))
{ text_error("incorrect dec2 decoupler flags! Should be 'nny' "); abort(1); }
if( dpwr2 > 46 )
{ text_error("don't fry the probe, DPWR2 too large! "); abort(1); }
if( pw > 50.0e-6 )
{ text_error("dont fry the probe, pw too high ! "); abort(1); }
if (pwHs > (gt1 +gstab1 -WFG_START_DELAY -2.0*SAPS_DELAY -2.0*POWER_DELAY -2.0*PWRF_DELAY))
{ text_error("pwHs is too long. Make pwHs shorter than %.1f microseconds",
(gt1 +gstab1 -WFG_START_DELAY -2.0*SAPS_DELAY -2.0*POWER_DELAY -2.0*PWRF_DELAY)*1.0e6);
abort(1);}
/*
if( pwN > 100.0e-6 )
{ text_error("dont fry the probe, pwN too high ! "); abort(1); }
*/
/* RELAXATION TIMES AND FLAGS */
/* evaluate maximum relaxT, relaxTmax chosen by the user */
rTnum = getarray("relaxT", rTarray);
relaxTmax = rTarray[0];
for (rTcounter=1; rTcounter<rTnum; rTcounter++)
if (relaxTmax < rTarray[rTcounter]) relaxTmax = rTarray[rTcounter];
/* compare relaxTmax with maxrelaxT */
if (maxrelaxT > relaxTmax) relaxTmax = maxrelaxT;
if ( ((T1rho[A]=='y') || (T2[A]=='y')) && (relaxTmax > d1) )
{ text_error("Maximum relaxation time, relaxT, is greater than d1 ! ");
abort(1); }
if ( ((T1[A]=='y') && (T1rho[A]=='y')) || ((T1[A]=='y') && (T2[A]=='y')) ||
((T1rho[A]=='y') && (T2[A]=='y')) )
{ text_error("Choose only one relaxation measurement ! "); abort(1); }
if ( ((T1[A]=='y') || (T1rho[A]=='y')) &&
((relaxT*100.0 - (int)(relaxT*100.0+1.0e-4)) > 1.0e-6) )
{ text_error("Relaxation time, relaxT, must be zero or
a multiple of 10 millisecs ! "); abort(1); }
if ( (T2[A]=='y') &&
(((relaxT+0.01)*50.0 - (int)((relaxT+0.01)*50.0+1.0e-4)) > 1.0e-6) )
{ text_error("Relaxation time, relaxT, must be
an odd multiple of 10 millisecs ! ");
abort(1); }
if ( ((T1rho[A]=='y') || (T2[A]=='y')) && (relaxTmax > 0.25) && (ix==1) )
{ printf("WARNING, sample heating evident in a reduced lock level,
may become substantial for maximum relaxation times, relaxT,
greater than 0.25 seconds ! "); }
if ( ((T1rho[A]=='y') || (T2[A]=='y')) && (relaxTmax > 0.5) )
{ text_error("Maximum relaxation times, relaxT, greater than 0.5 seconds will
produce undue sample heating from N15 irradiation ! "); abort(1); }
if ( ((NH2only[A]=='y') || (T1[A]=='y') || (T1rho[A]=='y') || (T2[A]=='y'))
&& (TROSY[A]=='y') )
{ text_error("TROSY not implemented with NH2 spectrum, or relaxation time
measurements. Set NH2only='n', T1='n','T1rho='n', T2='n',
or set TROSY='n' ! "); abort(1); }
if ((TROSY[A]=='y') && (dm2[C] == 'y'))
{ text_error("Choose either TROSY='n' or dm2='n' ! "); abort(1); }
/* PHASES AND INCREMENTED TIMES */
/* Phase incrementation for hypercomplex 2D data, States-Haberkorn element */
if (TROSY[A]=='y')
{ if (phase1 == 1) icosel = -1;
else { tsadd(t4,2,4); tsadd(t10,2,4); icosel = +1; }
}
else { if (phase1 == 1) {tsadd(t10,2,4); icosel = +1;}
else icosel = -1;
}
/* Set up f1180 */
tau1 = d2;
if((f1180[A] == 'y') && (ni > 1.0))
{ tau1 += ( 1.0 / (2.0*sw1) ); if(tau1 < 0.2e-6) tau1 = 0.0; }
tau1 = tau1/2.0;
/* Calculate modifications to phases for States-TPPI acquisition */
if( ix == 1) d2_init = d2;
t1_counter = (int) ( (d2-d2_init)*sw1 + 0.5 );
if(t1_counter % 2)
{ tsadd(t3,2,4); tsadd(t12,2,4); }
/* Correct inverted signals for NH2 only spectra */
if ((NH2only[A]=='y') && (T1[A]=='n') && (T1rho[A]=='n') && (T2[A]=='n'))
{ tsadd(t3,2,4); }
/* BEGIN PULSE SEQUENCE */
status(A);
obspower(tpwr);
obspwrf(4095.0);
decpower(pwClvl);
decpwrf(rf0);
dec2power(pwNlvl);
txphase(zero);
decphase(zero);
dec2phase(zero);
obsstepsize(1.0);
initval(phincr90,v11);
initval(phincr270,v12);
delay(d1);
/* xxxxxxxxxxxxxxxxx CONSTANT SAMPLE HEATING FROM N15 RF xxxxxxxxxxxxxxxxx */
if (T1rho[A]=='y')
{dec2power(slNlvl);
dec2rgpulse(relaxTmax-relaxT, zero, 0.0, 0.0);
dec2power(pwNlvl);}
if (T2[A]=='y')
{ncyc = 8.0*100.0*(relaxTmax - relaxT);
if (ncyc > 0)
{initval(ncyc,v1);
loop(v1,v2);
delay(0.625e-3 - pwN);
dec2rgpulse(2*pwN, zero, 0.0, 0.0);
delay(0.625e-3 - pwN);
endloop(v2);}
}
/* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx */
rcvroff();
if (TROSY[A]=='n')
dec2rgpulse(pwN, zero, 0.0, 0.0); /*destroy N15 magnetization*/
zgradpulse(gzlvl0, 0.5e-3);
delay(1.0e-4);
if (TROSY[A]=='n') dec2rgpulse(pwN, one, 0.0, 0.0);
zgradpulse(0.7*gzlvl0, 0.5e-3);
decpwrf(rfst);
txphase(t1);
delay(5.0e-4);
if ( dm3[B] == 'y' ) /* begins optional 2H decoupling */
{
lk_hold();
dec3rgpulse(1/dmf3,one,10.0e-6,2.0e-6);
dec3unblank();
dec3phase(zero);
delay(2.0e-6);
setstatus(DEC3ch, TRUE, 'w', FALSE, dmf3);
}
rgpulse(calH*pw,t1,0.0,0.0); /* 1H pulse excitation */
txphase(zero);
dec2phase(zero);
zgradpulse(gzlvl0, gt0);
delay(lambda - gt0);
sim3pulse(2.0*pw, 0.0, 2.0*pwN, zero, zero, zero, 0.0, 0.0);
txphase(one);
zgradpulse(gzlvl0, gt0);
delay(lambda - gt0);
rgpulse(pw, one, 0.0, 0.0);
xmtrphase(v11);
txphase(t2);
if (tpwrsf90<4095.0) { obspower(tpwrs+6.0); obspwrf(tpwrsf90); }
else obspower(tpwrs);
shaped_pulse("H2Osinc", pwHs, t2, 0.0, 0.0);
if (tpwrsf90<4095.0) obspwrf(4095.0);
obspower(tpwr);
xmtrphase(zero);
txphase(zero);
zgradpulse(gzlvl3, gt3);
dec2phase(t3);
delay(gstab);
dec2rgpulse(calN*pwN, t3, 0.0, 0.0);
decphase(zero);
/* xxxxxxxxxxxxxxxxxx OPTIONS FOR N15 RELAXATION xxxxxxxxxxxxxxxxxxxx */
if ( (T1[A]=='y') || (T1rho[A]=='y') || (T2[A]=='y') )
{
dec2phase(one);
zgradpulse(gzlvl4, gt4); /* 2.0*GRADIENT_DELAY */
delay(tNH - gt4 - 2.0*GRADIENT_DELAY);
sim3pulse(2.0*pw, 0.0, 2.0*pwN, zero, zero, one, 0.0, 0.0);
zgradpulse(gzlvl4, gt4); /* 2.0*GRADIENT_DELAY */
delay(tNH - gt4 - 2.0*GRADIENT_DELAY);
}
/* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx */
if (T1[A]=='y')
{
dec2rgpulse(pwN, one, 0.0, 0.0);
dec2phase(three);
zgradpulse(gzlvl0, gt0); /* 2.0*GRADIENT_DELAY */
delay(2.5e-3 - gt0 - 2.0*GRADIENT_DELAY - pw);
rgpulse(2.0*pw, zero, 0.0, 0.0);
delay(2.5e-3 - pw);
ncyc = (100.0*relaxT);
initval(ncyc,v4);
if (ncyc > 0)
{loop(v4,v5);
delay(2.5e-3 - pw);
rgpulse(2.0*pw, two, 0.0, 0.0);
delay(2.5e-3 - pw);
delay(2.5e-3 - pw);
rgpulse(2.0*pw, zero, 0.0, 0.0);
delay(2.5e-3 - pw);
endloop(v5);}
dec2rgpulse(pwN, three, 0.0, 0.0);
}
/* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx */
/* Theory suggests 8.0 is better than 2PI as RF */
/* field multiplier and experiment confirms this.*/
if (T1rho[A]=='y') /* Shift evolution of 2.0*pwN/PI for one pulse */
{ /* at end left unrefocused as for normal sequence*/
delay(1.0/(8.0*slNrf) - pwN);
decrgpulse(pwN, zero, 0.0, 0.0);
dec2power(slNlvl);
/* minimum 5ms spinlock to dephase */
dec2rgpulse((2.5e-3-pw), zero, 0.0, 0.0); /* spins not locked */
sim3pulse(2.0*pw, 0.0, 2.0*pw, zero, zero, zero, 0.0, 0.0);
dec2rgpulse((2.5e-3-pw), zero, 0.0, 0.0);
ncyc = 100.0*relaxT;
initval(ncyc,v4); if (ncyc > 0)
{loop(v4,v5);
dec2rgpulse((2.5e-3-pw), zero, 0.0, 0.0);
sim3pulse(2.0*pw, 0.0, 2.0*pw, two, zero, zero, 0.0, 0.0);
dec2rgpulse((2.5e-3-pw), zero, 0.0, 0.0);
dec2rgpulse((2.5e-3-pw), zero, 0.0, 0.0);
sim3pulse(2.0*pw, 0.0, 2.0*pw, zero, zero, zero, 0.0, 0.0);
dec2rgpulse((2.5e-3-pw), zero, 0.0, 0.0);
endloop(v5);}
dec2power(pwNlvl);
decrgpulse(pwN, zero, 0.0, 0.0);
delay(1.0/(8.0*slNrf) + 2.0*pwN/PI - pwN);
}
/* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx */
if (T2[A]=='y')
{
dec2phase(zero);
initval(0.0,v3); initval(180.0,v4);
ncyc = 100.0*relaxT;
initval(ncyc,v5);
loop(v5,v6);
initval(3.0,v7);
loop(v7,v8);
delay(0.625e-3 - pwN);
dec2rgpulse(2.0*pwN, zero, 0.0, 0.0);
delay(0.625e-3 - pwN);
endloop(v8);
delay(0.625e-3 - pwN - SAPS_DELAY);
add(v4,v3,v3); xmtrphase(v3); /* SAPS_DELAY */
dec2rgpulse(2.0*pwN, zero, 0.0, 0.0);
delay(0.625e-3 - pwN - pw);
rgpulse(2*pw, zero, 0.0, 0.0);
delay(0.625e-3 - pwN - pw );
dec2rgpulse(2.0*pwN, zero, 0.0, 0.0);
xmtrphase(zero); /* SAPS_DELAY */
delay(0.625e-3 - pwN - SAPS_DELAY);
initval(3.0,v9);
loop(v9,v10);
delay(0.625e-3 - pwN);
dec2rgpulse(2.0*pwN, zero, 0.0, 0.0);
delay(0.625e-3 - pwN);
endloop(v10);
endloop(v6);
}
/* xxxxxxxxxxxxxxxxxx OPTIONS FOR N15 EVOLUTION xxxxxxxxxxxxxxxxxxxxx */
txphase(zero);
dec2phase(t9);
if (NH2only[A]=='y') /* NH2 only experiment */
{
delay(tau1);
/* optional sech/tanh pulse in middle of t1 */
if (C13refoc[A]=='y') /* WFG_START_DELAY */
{decshaped_pulse("stC200", 1.0e-3, zero, 0.0, 0.0);
delay(tNH - 1.0e-3 - WFG_START_DELAY - 2.0*pw);}
else
{delay(tNH - 2.0*pw);}
rgpulse(2.0*pw, zero, 0.0, 0.0);
if (tNH < gt1 + 1.99e-4) delay(gt1 + 1.99e-4 - tNH);
delay(tau1);
dec2rgpulse(2.0*pwN, t9, 0.0, 0.0);
if (mag_flg[A] == 'y') magradpulse(icosel*gzcal*gzlvl1, gt1);
else zgradpulse(icosel*gzlvl1, gt1); /* 2.0*GRADIENT_DELAY */
txphase(t4);
dec2phase(t10);
if (tNH > gt1 + 1.99e-4) delay(tNH - gt1 - 2.0*GRADIENT_DELAY);
else delay(1.99e-4 - 2.0*GRADIENT_DELAY);
}
else if ((T1[A]=='y') || (T1rho[A]=='y') || (T2[A]=='y')) /* RELAXATION EXPERIMENTS */
{
delay(tau1);
/* optional sech/tanh pulse in middle of t1 */
if (C13refoc[A]=='y') { /* WFG_START_DELAY */
decshaped_pulse("stC200", 1.0e-3, zero, 0.0, 0.0);
/* for 180 flipback pulse use tpwrsf180 fine power and add 6db to coarse power */
if (tpwrsf180<4095.0) {
txphase(two);
obspower(tpwrs180+6.0); obspwrf(tpwrsf180);
delay(tNH -1.0e-3 -pwHs -WFG2_START_DELAY -2.0*pw -WFG_START_DELAY
-2.0*SAPS_DELAY -2.0*POWER_DELAY -2.0*PWRF_DELAY);
shaped_pulse("H2Osinc", pwHs, two, 0.0, 0.0);
txphase(zero);
obspower(tpwr); obspwrf(4095.0);
} else {
txphase(two);
obspower(tpwrs180);
delay(tNH -1.0e-3 -pwHs -WFG2_START_DELAY -2.0*pw -WFG_START_DELAY
-2.0*SAPS_DELAY -2.0*POWER_DELAY);
shaped_pulse("H2Osinc", pwHs, two, 0.0, 0.0);
txphase(zero);
obspower(tpwr);
}
/*delay(tNH - 1.0e-3 - WFG_START_DELAY - 2.0*pw);*/
} else {
/* for 180 flipback pulse use tpwrsf180 fine power and add 6db to coarse power */
if (tpwrsf180<4095.0) {
txphase(two);
obspower(tpwrs180+6.0); obspwrf(tpwrsf180);
delay(tNH -2.0*pw -pwHs -WFG_START_DELAY -2.0*SAPS_DELAY
-2.0*POWER_DELAY -2.0*PWRF_DELAY);
shaped_pulse("H2Osinc", pwHs, two, 0.0, 0.0);
txphase(zero);
obspower(tpwr); obspwrf(4095.0);
} else {
txphase(two);
obspower(tpwrs180);
delay(tNH -2.0*pw -pwHs -WFG_START_DELAY -2.0*SAPS_DELAY -2.0*POWER_DELAY);
shaped_pulse("H2Osinc", pwHs, two, 0.0, 0.0);
txphase(zero);
obspower(tpwr);
}
/*delay(tNH - 2.0*pw);*/
}
rgpulse(2.0*pw, zero, 0.0, 0.0);
if (tNH < gt1 + 1.99e-4) delay(gt1 + 1.99e-4 - tNH);
delay(tau1);
dec2rgpulse(2.0*pwN, t9, 0.0, 0.0);
if (mag_flg[A] == 'y') magradpulse(icosel*gzcal*gzlvl1, gt1);
else zgradpulse(icosel*gzlvl1, gt1); /* 2.0*GRADIENT_DELAY */
txphase(t4);
dec2phase(t10);
if (tNH > gt1 + 1.99e-4) delay(tNH - gt1 - 2.0*GRADIENT_DELAY);
else delay(1.99e-4 - 2.0*GRADIENT_DELAY);
}
else if (TROSY[A]=='y') /* TROSY EXPERIMENT */
{
if ( (C13refoc[A]=='y') && (tau1 > 0.5e-3 + WFG2_START_DELAY) )
{delay(tau1 - 0.5e-3 - WFG2_START_DELAY); /* WFG2_START_DELAY */
decshaped_pulse("stC200", 1.0e-3, zero, 0.0, 0.0);
delay(tau1 - 0.5e-3);}
else delay(2.0*tau1);
if (mag_flg[A] == 'y') magradpulse(icosel*gzcal*gzlvl1, gt1);
else zgradpulse(icosel*gzlvl1, gt1); /* 2.0*GRADIENT_DELAY */
delay(gstab1 - 2.0*GRADIENT_DELAY);
dec2rgpulse(2.0*pwN, t9, 0.0, 0.0);
xmtrphase(v12);
txphase(three);
if (tpwrsf270<4095.0)
{
delay(gt1 +gstab1 -pwHs -5.0e-5 -2.0*POWER_DELAY -2.0*PWRF_DELAY);
obspwrf(tpwrsf270); obspower(tpwrs+6.0);
shaped_pulse("H2Osinc", pwHs, three, 0.0, 0.0);
obspower(tpwr); obspwrf(4095.0);
}
else
{
delay(gt1 +gstab1 -pwHs -5.0e-5 -2.0*POWER_DELAY);
obspower(tpwrs);
shaped_pulse("H2Osinc", pwHs, three, 0.0, 0.0);
obspower(tpwr);
}
xmtrphase(zero);
txphase(t4);
delay(5.0e-5);
}
else /* REGULAR HSQC EXPERIMENT */
{
if (dm2[C]=='n') /* fully-coupled spectrum */
{
if ( (C13refoc[A]=='y') && (tau1 > 0.5e-3 +WFG2_START_DELAY) ) {
delay(tau1 -0.5e-3 -WFG_START_DELAY); /* WFG_START_DELAY */
decshaped_pulse("stC200", 1.0e-3, zero, 0.0, 0.0);
delay(tau1 -0.5e-3);
delay(gt1 +gstab1);
} else {
delay(2.0*tau1);
delay(gt1 +gstab1);
}
}
else /* decouple 1H in t1 */
{
if ( (C13refoc[A]=='y') && (tau1 > 0.5e-3 + WFG2_START_DELAY) ) {
delay(tau1 - 0.5e-3 - WFG2_START_DELAY); /* WFG2_START_DELAY */
simshaped_pulse("", "stC200", 2.0*pw, 1.0e-3, zero, zero, 0.0, 0.0);
/* for 180 flipback pulse use tpwrsf180 fine power and add 6db to coarse power */
if (tpwrsf180<4095.0) {
txphase(two);
obspower(tpwrs180+6.0); obspwrf(tpwrsf180);
shaped_pulse("H2Osinc", pwHs, two, 0.0, 0.0);
txphase(zero);
obspower(tpwr); obspwrf(4095.0);
delay(gt1 +gstab1 -pwHs -WFG_START_DELAY
-2.0*SAPS_DELAY -2.0*POWER_DELAY -2.0*PWRF_DELAY);
} else {
txphase(two);
obspower(tpwrs180);
shaped_pulse("H2Osinc", pwHs, two, 0.0, 0.0);
txphase(zero);
obspower(tpwr);
delay(gt1 +gstab1 -pwHs -WFG_START_DELAY -2.0*SAPS_DELAY -2.0*POWER_DELAY);
}
delay(tau1 - 0.5e-3);
} else {
delay(tau1);
rgpulse(2.0*pw, zero, 0.0, 0.0);
/* for 180 flipback pulse use same fine power and add 6db to coarse power */
if (tpwrsf<4095.0) {
txphase(two);
obspower(tpwrs+12.0); obspwrf(tpwrsf180);
shaped_pulse("H2Osinc", pwHs, two, 0.0, 0.0);
txphase(zero);
obspower(tpwr); obspwrf(4095.0);
delay(gt1 +gstab1 -2.0*pw -pwHs -WFG_START_DELAY
-2.0*SAPS_DELAY -2.0*POWER_DELAY -2.0*PWRF_DELAY);
} else {
txphase(two);
obspower(tpwrs+6.0);
shaped_pulse("H2Osinc", pwHs, two, 0.0, 0.0);
txphase(zero);
obspower(tpwr);
delay(gt1 +gstab1 -2.0*pw -pwHs -WFG_START_DELAY -2.0*SAPS_DELAY -2.0*POWER_DELAY);
}
delay(tau1);
}
}
dec2rgpulse(2.0*pwN, t9, 0.0, 0.0);
if (mag_flg[A] == 'y') magradpulse(icosel*gzcal*gzlvl1, gt1);
else zgradpulse(icosel*gzlvl1, gt1); /* 2.0*GRADIENT_DELAY */
txphase(t4);
dec2phase(t10);
delay(gstab1 - 2.0*GRADIENT_DELAY);
}
if (T1rho[A]=='y') delay(POWER_DELAY);
/* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx */
if (TROSY[A]=='y') rgpulse(pw, t4, 0.0, 0.0);
else sim3pulse(pw, 0.0, pwN, t4, zero, t10, 0.0, 0.0);
txphase(zero);
dec2phase(zero);
zgradpulse(gzlvl5, gt5);
if (TROSY[A]=='y') delay(lambda - 0.65*(pw + pwN) - gt5);
else delay(lambda - 1.3*pwN - gt5);
sim3pulse(2.0*pw, 0.0, 2.0*pwN, zero, zero, zero, 0.0, 0.0);
zgradpulse(gzlvl5, gt5);
txphase(one);
dec2phase(t11);
delay(lambda - 1.3*pwN - gt5);
sim3pulse(pw, 0.0, pwN, one, zero, t11, 0.0, 0.0);
txphase(zero);
dec2phase(zero);
zgradpulse(1.5*gzlvl5, gt5);
delay(lambda - 1.3*pwN - gt5);
sim3pulse(2.0*pw, 0.0, 2.0*pwN, zero, zero, zero, 0.0, 0.0);
dec2phase(t10);
zgradpulse(1.5*gzlvl5, gt5);
if (TROSY[A]=='y') delay(lambda - 1.6*pwN - gt5);
else delay(lambda - 0.65*pwN - gt5);
if (TROSY[A]=='y') dec2rgpulse(pwN, t10, 0.0, 0.0);
else rgpulse(pw, zero, 0.0, 0.0);
delay(gt2 +gstab - 0.65*pw + 2.0*GRADIENT_DELAY + POWER_DELAY);
if ( dm3[B] == 'y' ) /* turns off 2H decoupling */
{
setstatus(DEC3ch, FALSE, 'c', FALSE, dmf3);
dec3rgpulse(1/dmf3,three,2.0e-6,2.0e-6);
dec3blank();
lk_autotrig(); /* resumes lock pulsing */
}
rgpulse(2.0*pw, zero, 0.0, 0.0);
dec2power(dpwr2); /* POWER_DELAY */
if (mag_flg[A] == 'y') magradpulse(gzcal*gzlvl2, gt2);
else zgradpulse(gzlvl2, gt2); /* 2.0*GRADIENT_DELAY */
delay(0.5*gstab);
rcvron();
statusdelay(C,0.5*gstab);
if (dm3[B] == 'y') {delay(1/dmf3); lk_sample();}
setreceiver(t12);
}