During recording, the signal feeds alternately to the heads via a head switching circuit. The head is turned ON as it touches the tape and makes its half-circle pass around the head drum. Just before the head is about to leave the tape, it turns OFF and the signal is applied to the opposite head. The video waveform for head switching is shown in Fig. 33.27.
Fig. 33.27 The action of switching the video heads ON and OFF as the video drum rotates