Equalizing Pulse

a narrow pulse superimposed on the vertical blanking pulse of a composite television signal before and after the vertical synchronizing pulse. Equalizing pulses are added to the synchronizing signal in interlaced scanning in order to eliminate the difference in the form of the odd and even vertical synchronizing pulses; the difference in form, which appears when the vertical synchronizing pulses are extracted from the synchronizing signal by means of an integrated filter, is due to the different location of the line synchronizing pulses. The duration of an equalizing pulse is approximately 2.5 microseconds, and the repetition frequency is twice the line frequency. The number of equalizing pulses depends on the identity requirements for the even and odd vertical synchronizing pulses and is usually five or six.