The behaviour of nuclear quadrupole resonance (NQR) signal was studied after applying additional RF pulses to the spin-system which was previously prepared to be in the equilibrium or steady-state. The experiments revealed some peculiarities in the behaviour of the signals which are important for the understanding of the dynamic properties of the quadrupolar spin-system. The experimental results are presented for 4-cyanoperidine and sodium nitrite. (c) 2006 Elsevier B.V. All rights reserved.