\\   +a (0+\exp{\left(-t_r/T_{0n} \right)})\\ \end{array}% \right) \rightarrow {\rm delay}~t_r \rightarrow \left(% \begin{array}{c}   -a (0-\exp{\left(-t_r/T_{0n} \right)}) \\   -a (0+\exp{\left(-t_r/T_{0n} \right)})\\   +a (0-\exp{\left(-t_r/T_{0n} \right)})\\   +a (0+\exp{\left(-t_r/T_{0n} \right)})\\ \end{array}% \right)$$ 