Analog Waveform Symbol Generation

Figure 1-7.—The AN/UYA-4(V) symbol set. Two different methods of painting symbols are currently in use in the AN/UYA-4(V) display group. They are the analog waveform and the digital stroke methods. The symbols being generated are the same in either case, only the methods used to generate the symbols differ. Figure 1-7 shows the symbol set used in the AN/UYA-4(V) display group. The AN/UYQ-21(V) computer display set has an expanded symbol set and develops sweep and symbols using both the digital stroke method and raster-scan CRTs, depending on the type of console. Figure 1-8 shows the AN/UYQ-21(V) symbol set. Analog Waveform Symbol Generation To help you to fully understand the analog waveform generation process, we look at the equipments required and the procedure that takes place. Analog symbols are formed by applying harmonious waveforms to the deflection plates of a CRT. For example, if two sine waves of equal amplitude and 90-degrees out of phase are applied to the X and Y axes of a CRT, a circle will be displayed on the CRT. By adding the Z, or unblinking signal, we can control what part of the circle is actually displayed and thus form the symbol. Ellipses are formed when the amplitudes of the two sine waves are unequal. Using the same principle with two trapezoid waveforms that are 90-degrees out of phase, a square will be formed. 1-8