FINDING THE 90^O  PULSE – pw90 -  π/2

1. Tune probe with your sample, lock, shim, and then take a single scan spectrum with your  pw<<pw90,  nt=1  ss=0

2.  Phase, baseline correct, and use cursors to expand and narrow in on a peak separated from the other peaks.

3.  Set  d1 = 10 sec,   turn off autogain,  set vp=50

4.  Create an array of pulse widths to be used around the estimated  360^o pulse  (which will be 4 x  the current pw90)

          for example:  if   pw90 = 7.5      4 x 7.5 = 30

          pw = 28, 30, 32, 34, 36, 40

5.  The more polar the solution or the colder the solution, the longer the pw90 will be.

6.  Type  ga   and watch the results.  The pulse width should ideally be a sine wave with  90 +,  180  null, 270  -,  360 null

          you are looking for the null with the peaks going from

                   negative to null to positive

7.  To display the series, type  dssh,    da will display the array values.

8.  The pw90  is the null (360) divided by 4.   Enter this into your parameter set tab     (AQS & OBS)