# Translations:Ghost reflection/6/en

Thus, whether we measure pressure or particle velocity, the ghost reflection is of opposite polarity to that of the direct pulse. The delay time between the direct pulse and the ghost is equal to the two-way traveltime from the shot to the upper interface. If this delay is represented by *T* discrete time units and if the ideal explosive pulse is a spike of unit amplitude, then the composite wavelet for particle velocity has the form (–1,0, 0, …,0, 1,0, 0, …), and the composite wavelet for pressure has the form (1, 0, 0, …, 0, –1, 0, 0, …), where there are *T* – 1 zeros between the primary spike and the ghost spike. Figure 4a shows the downgoing direct-wave/ghost-wave complex with amplitude in terms of pressure. Figure 4b shows the corresponding complex in terms of particle velocity. In these figures, the spike series have been convolved with an arbitrary waveshape.