Pulse: The waveform of voltage (V) or current (A) is like the waveform of pulse beating on ECG. But what about the power pulse and sound pulse we hear now? In fact, these are all extended from the original intention of the pulse. In other words, pulse wave is a signal waveform generated in the form of impact. From small to large, the square wave is jumping and stable.
The academic definition of pulse wave: the mechanical forms such as waves emitted at the same time will suddenly change in a short time, and then quickly return to the initial value, which is called pulse.
Just as sine wave can be characterized by amplitude, frequency and initial phase, an ideal rectangular pulse can be described clearly with only three parameters. These three parameters are pulse amplitude Um, pulse repetition period t and pulse width tw.
However, due to the influence of energy storage elements in the actual circuit, the pulse waveform is not very regular, so more parameters are needed to describe its characteristics, such as:
Pulse amplitude Um.
Pulse leading edge and rising time tr
Pulse trailing edge and falling time
Pulse width tw
Pulse interval tg
Pulse period t
Pulse frequency f
From the definition of pulse, we can't see that pulse has the characteristics of interval, so we can take pulse as a signal. The definition of pulse signal comes from this: compared with a continuous signal that appears for a short time in the whole signal period, there is no signal in most signal periods. Just like a person's pulse. Now it generally refers to digital signals, and there is a signal half the time (or even longer) in a cycle. The signal in the computer is a pulse signal, also known as a digital signal.
Next, let's look at square waves and pulse waves. Square wave, named for its square shape. And pulse waves. The maximum amplitude duration of waveforms is exactly the same, but they are also called square waves separately. That is to say, as long as the duration of the maximum amplitude up and down the waveform is different, it is a pulse wave.