The process of maintaining one operation in step with another. The commonest example is the electric clock, whose motor rotates at some integral multiple or submultiple of the speed of the alternator in the power station. In television, synchronization is essential in order that the electron beams of receiver picture tubes will be at exactly the same spot on the screen at each instant as is the beam in the television camera tube at the transmitter. Synchronism in television is achieved by transmitting a synchronizing pulse at the end of each scanning line, to make all receivers move simultaneously to the start of the next line. A similar vertical synchronizing pulse is transmitted when the camera beam reaches the bottom of the picture, to make all beams go back to the top for the start of the next field.