gusucode.com > qit_matlab_0.10.0工具箱源码程序 > qit/+seq/cpmg.m
function s = cpmg(t, n) % CPMG Carr-Purcell-Meiboom-Gill sequence. % s = cpmg(t, n) % % Returns the Carr-Purcell-Meiboom-Gill sequence of n repeats with waiting time t. % The purpose of the CPMG sequence is to facilitate a T_2 measurement % under a nonuniform z drift, it is not meant to be a full memory protocol. % The target operation for this sequence is identity. % Ville Bergholm 2007-2011 s = seq.nmr([pi/2, pi/2]); % initial y rotation % step: wait, pi x rotation, wait step_tau = [t; pi; t]; step_ctrl = [0 0; 1 0; 0 0]; for k=1:n s.tau = [s.tau; step_tau]; s.control = [s.control; step_ctrl]; end