CPMG pulse program with HADC digitizer and analog filtering for AVANCE AQX.
Contribution of Y. Millot
J. T. Cheng and P. D. Ellis ( J. Phys. Chem. 93, 2549-2555, 1989) studied the adsorption of Rb+ to γ-alumina using CPMG echo train pulse sequence. The Fourier transform of the fid followed by the train of m echoes is a spikelet spectrum. The latter has a better signal-to-noise ratio than that from one-pulse experiment.
;Carr-Purcell-Meiboom-Gill echo train acquisition with analog filtering ;and HADC digitizer #include <Avance.incl> define delay dx define delay px "l2 = 2*l1" "l4 = l3*l2 + l1" "dx = dw" "px = dw" ze ; clear memory, new data replace old data. start, d1 pl1:f1 ; recycle duration. p1:f1 ph1 ; 90° pulse with x phase. d11 ; echo delay d11 + d14. d14 ; echo delay d11 + d14. p2:f1 ph2 ; 180° refocussing pulse with y phase. d11 adc ph31 ; echo delay d11 + d14. d14:e ph0 syrec ; echo delay d11 + d14. fid, dx ; dx + px, the dwell time for the external dwell-pulse. px:x ; external dwell-pulse for the fid data digitizing. lo to fid times l1 ; loop for the fid data digitizing. nbecho, d11:e ; echo delay d11 + d14, sytra not required. d14:e ; echo delay d11 + d14. p2:f1:e ph3 ; 180° refocussing pulse with y phase. d11:e syrec ; echo delay d11 + d14. d14:e ph0 ; echo delay d11 + d14. echo, dx ; dx + px, the dwell time for the external dwell-pulse. px:x ; external dwell-pulse for an echo data digitizing. lo to echo times l2 ; loop for an echo data digitizing. 0.1u lo to nbecho times l3 ; loop for the echo train acquisition. rcyc=start ; loop to start, ns times for averaging. 100m wr #0 ; delay for disk I/O, store signal. ;------------------------------------- tmp, 100u lo to tmp times l4 ; provide the time-domain size td = 2*l4. ;------------------------------------- exit ; end of the pulse program. ph1 = 0 0 1 1 2 2 3 3 ; f1 channel p1 pulse phase ph2 = 1 3 2 0 3 1 0 2 ; f1 channel first p2 pulse phase ph3 = 1 3 2 0 3 1 0 2 3 1 0 2 1 3 2 0 ; f1 channel second p2 pulse phase ph31 = 0 0 1 1 2 2 3 3 ; receiver phase ph0 = 0 ; receiver reference phase ;pl1: f1 channel power level for p1 and p2 pulses ;d11: 10u ;l1: number of digitized points for the fid ;l2: number of digitized points for an echo ;l3: number of echoes ;ns = 16*n ;2*dw = dx + px, dwell-time for the external dwell-pulse ;aq = 2*dw*l4 = dw*td