Because a square wave can move quickly from one value to another (i.e., 0→1 or 1→0), it is used as a clock signal to accurately trigger synchronization circuits. However, if a square wave is represented in the frequency-defined domain, a series of harmonics can occur. This may generate electromagnetic waves and current pulses, affecting the surrounding circuits, generating noise and errors, and affecting some precision instruments such as analog-to-digital converters very significantly, so the design will use a sine wave as the clock signal to replace the square wave. In general, square waves are generally used as clock signals.
Triangle waveforms, also known as sawtooth waveforms, are mainly used in the scanning circuits of CRTs for display devices. Such as oscilloscopes, picture tubes, monitors, etc. CRT is composed of many points. CRT is composed of many dots. To form a grating, it is necessary to have an electron beam to bombard these light-emitting dots. Scanning circuits are divided into horizontal and vertical scanning. The CRT can be scanned one line or one frame at a time. The electron beam starts at one end of the first row or frame, sweeps to the other end, and then returns to scan the second row or frame. ....... A triangle wave is characterized by a gradual increase in voltage and a sudden drop to zero. It is suitable for use in scanning circuits. Fourth, the sine wave signal and triangular wave signal generation
From the modulation circuit can be seen, to produce SPWM signal, there must be a sine wave signal and triangular wave signal. Because the sine wave UPS in the absence of utility power also to provide sinusoidal voltage to the load, and at this time there is no utility power, so the sine wave signal and triangle wave signal must be generated by the UPS circuit itself. Among them, the generation of triangle wave is relatively easy, the more difficult is the sine wave signal. This sine wave signal generated by the UPS itself is called the native sine wave signal.