Protocol: Tancpxidref  Sequence: tancpxidref.c  Apptype: solidseq1d

Description: 

Interrupted decoupling for suppression of the signals of protonated X 
nuclei follows constant, linear or tangent-ramped cross polarization 
(CP) between protons and X with a choice of SPINAL64 or TPPM 
decoupling. Provides a refocusing pulse, synchronized with two rotor 
periods to avoid a large first order phase correction. Used to edit 
protonated carbons from a CPMAS spectrum. 
   
Setup: 

Load a calibrated data set and select the protocol Tancpxidref.  For a 
new nucleus calibrate CP with Onepul and Tancpx and then select 
Tancpxidref.  

Select the desired decoupling method, TPPM or SPINAL. The manual file 
onepul describes calibration of decoupling. 

Be sure the MAS Rate on the Acquisition page is set correctly. 

Set aXidref = aX90 and pwXidrex = 2.0*aX90. 

Set tXidref to about 100 us to dephase X nuclei with attached protons. 
Fine adjust tXidref for the best suppression.  Methyl groups do not 
dephase easily. 

Parameter  Groups: 

90H:  Module:  no
Sequence:  tancpx.c  
Description:  Provides a 90-degree pulse on dec that can be used as a 
              preparation pulse. Also used to store the dec calibration.
Parameters:  Channels Page
       aH90  - the amplitude of the pulse.
       pwH90 - the pulse length.

cpHX:  Module:  yes
Sequence:  tancpx.c
Description:  Implements constant, linear or tangent-ramped cross 
              polarization from dec to obs. 
Parameters:  Sequence Page
       shHX - 'c', constant, 'l', linear and 't', tangent shape on the 
              channel designated with chHX. 
       chHX - the variable-amplitude channel, 'fr' from or 'to', to. 
       aHhx - median amplitude of the dec channel.
       aXhx - median amplitude of the obs channel.
       bHX - +/- tangent curvature (>0 to 1.0e5).  
       dHX - amplitude width of the ramp. A negative width sets a ramp 
              that starts high and decreases in amplitude.
       tHX - contact time
       ofHX - overall offset on the variable channel
       frHX = 'dec' -  channel with the initial polarization (must be 
              set - not shown).           
       toHX = 'obs' -  channel with the final polarization (must be set 
              - not shown). 
Implementation:  CP hx = getcp("HX",0.0,0.0,0,1); 
Underscore functions: _cp_(hx,phHhx,phXhx);  

idrefX:  Module:  yes 
Sequence:  tancpxidref.c 
Description:  Implements interrupted decoupling of the current 
              decoupling sequence on dec with a refocusing pulse on 
              obs. The interrupted decoupling is applied before the 
              refocusing pulse.
Parameters:  Sequence Page
       aXidref - amplitude of the obs pulse. 
       pwXidref - 180-degree flip angle on the obs channel.
       t1Xidref - delay for interrupted decoupling. 
       chXidref = 'obs' must be set (not shown).
Implementation: WMPA ref = getidref("idrefX"); DSEQ dec = getdseq("H"); 
Underscore function: _idref(ref, dec, phXref);  phXref is the phase 
              table of pwXidref.   

Hseq:  Module:  yes 
Sequence:  tancpx.c      
Description:  Chooses SPINAL or TPPM decoupling on the dec channel 
              during acquisition.
Parameters:  Sequence Page - the Hspinal and Htppm groups overlap. 
       Hseq - chooses the decoupling sequence, TPPM or SPINAL. 
Implementation:  DSEQ dec = getdseq("H");  The router implements 
              getspinal() or gettppm(). 
Underscore functions: _dseqon(dec); runs _tppm(); or _spinal();
              _dseqoff(dec); runs decprgoff();  

Hspinal:  Module:  yes 
Sequence: tancpx.c  
Description:  Implements SPINAL decoupling on the dec channel during 
              acquisition.  
Parameters:  Sequence Page
       aHspinal - amplitude of the dec channel. 
       pwHspinal - approximate 180-degree flip angle on resonance. 
       phHspinal - +/- small angle phase. SPINAL64 is implemented with 
              phases = +/- 1.0, +/- 1.5 and +/-2.0 times phHspinal. 
       chHspinal = 'dec' must be set (not shown).
Implementation: SPINAL dec = getspinal("H"); or DSEQ dec = 
              getdseq("H");  
Underscore functions: _spinal(dec); and decprgoff(); or _dseqon(dec); 
              and _dseqoff(dec);   

Htppm:  Module:  yes 
Sequence:  tancpx.c      
Description:  Implements TPPM decoupling on the dec channel during 
              acquisition.  
Parameters:  Sequence Page
       aHtppm - amplitude of the dec channel. 
       pwHtppm - approximate 180-degree flip angle on resonance. 
       phHtppm - +/- small angle phase. TPPM is implemented 
              with phases = +/- 1.0 times phHtppm for alternating pulses.  
       chHtppm = 'dec' must be set (not shown).
Implementation: TPPM dec = gettppm("H"); or DSEQ dec = getdseq("H");   
Underscore functions: _tppmon(dec); and decprgoff(); or _dseqon(dec); 
              and _dseqoff(dec);   

