Answer: The pulse signal belongs to the \"switching signal\". The output frequency of the pulse represents the instantaneous flow rate. The pulse signal is a discrete signal with a variety of shapes, and compared with ordinary analog signals (such as sine waves), the waveform is discontinuous in the Y-axis (there is a clear interval between the waveform and the waveform), but it has a certain periodicity. The most common type of pulse is a rectangular wave (also known as a square wave).
Pulse signal can be used to represent information, can also be used as a carrier, such as pulse code modulation (PCM) in pulse modulation, pulse width modulation (PWM), etc., can also be used as a variety of digital circuits, high-performance chips
The 485 signal is a \"modulated signal\" that transmits the current instantaneous flow through the serial port by means of communication.
485 is to solve the problem of 232 communication distance.
First of all, the 485 signal is also a pulse signal, but the pulse frequency and width are changed at any time, and the polarity of the pulse voltage is also changed.
In general, the said pulse signal either has a constant frequency and pulse width, or one of the changes, but the polarity is generally not changed. By changing the frequency or pulse width, analog signals can be transmitted, as well as digital signals.