aints images on a screen. When the cathode gets hot, it causes electrons to stream from a device called an electron gun. The beam of electrons, sometimes referred to as a reproducing spot, continuously bombards the inside surface of a monitor. The beam traces its course in a series of thin lines, and strikes phosphor dots that coat the inside of the monitor. When hit with an electron, an individual phosphor emits light. Video IF response RF tuner response Sound carrier Sound IF response Picture carrier Video-amplifier response 4.5Mhz Horizontal Color sync pulse burst Burst of 3.58 Mhz (8 cycles min.) Figure 5-10. Color Burst (Michel Bayard). Frame rates differ between video applications. Television standards specify that video frames be sent at a rate of between 25-30 per second, depending on the standard. Scanning systems reflect the electrical systems that exist in a country. In Europe and other parts of the world that Europeans colonized, the national electrical system operates at 50 Hz. In the U.S. and most of the rest of the world, the electrical system delivers alternating current at a rate of 60 Hz. These differences caused television systems to evolve dissimilarly. The U.S., Mexico, Canada, and Japan (and 19 other countries) use the NTSC system. Europe, Australia, Africa and parts of Asia and South America use a television system that specifies 25 fps. The number of lines of resolution varies from 625 in England and much of Western Europe, to 819 in France, Russia, and Eastern Europe. Although we have just asserted that North American television incorporates a rate of 30 frames per second, adding color to the television signal requires that the rate drop to 29.97 fps (most people round it to 30). Each 525-line video frame is divided into two halves, each of which is called a field. One of the 262.5-line fields contains the Video Communications: The Whole Picture odd scan lines, and the other contains the even ones. During display, first the odd- line field then the even field is painted in a process calle