What is the principle of square wave modulation and the waveform generation process?

乱世煮酒论天下

What is the principle of square wave modulation and the waveform generation process? [Copy link]

In the square wave modulation generation process in the simulation software, square wave modulation can use triangular wave and DC signal to generate square waves with different duty cycles through a comparator. Controlling the frequency of the triangular wave can control the frequency of the output square wave, and controlling the amplitude of the DC signal can control the duty cycle of the output square wave. If square wave modulation is used to control the opening of a single-phase inverter bridge, how are square waves with different duty cycles generated in an embedded system, that is, in actual use?

maychang

[How do you generate square waves with different duty cycles in embedded systems, that is, in actual use? ]

To generate square waves with different duty cycles, a sawtooth wave or a sawtooth-like wave (the rise and fall are not straight lines but exponential curves close to a straight line) is still compared with a horizontal straight line (DC voltage). The duty cycle of the square wave generated in this way is not linearly related to the DC voltage, but close to a linear relationship.

maychang

The approximate sawtooth waveform is shown in the figure below. The rise and fall are not straight lines but exponential curves. However, compared with the horizontal straight line, rectangular waves with different duty cycles can still be generated.

freebsder

It is just an IO up and down change, but pwm is a special IP to generate the IO up and down change