We have a problem to achieve the following simple 'pulse program' under UXNMR,
intended to control the on-time of an external gradient unit in the Hahn echo:
1 p1 etc...
2 wait d4 (typically 1ms)
3 set a bit on, by the setf^-facility
4 vd
5 set the control bit off again
6 then comes the problem - wait d31 (=d10-d4-vd) to generate the
7 next rf pulse (2*p1) at exactly a time d10 after the first pulse
8... repeat 2-5 again and acquire the echo at 2*d10 after line 1
UXNMR pulse programming does not seem allow 'vd' to be used arithmetically
in the same way as other 'fixed' delays' , i.e.
like using d31 at line 6 (that would previously have been evaluated
as d31=d10-d4-vd, before 'line 1' - but that line will not compile)
We tried a lot of 'wild' variants, but none seem to work.
There probably is a simple solution to this. Does any of you know it
already ?
Many thanks in advance for any help
Peter Stilbs
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Peter Stilbs, Prof. tel: +46 8 7908201
Physical Chemistry fax: +46 8 7908207
Royal Institute of Technology (KTH) E-mail: peter@physchem.kth.se
S-100 44 Stockholm, Sweden
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