PULSES

Here is the characteristics of a single pulse.The voltage rises very rapidly from zero to its maximum value.
It stays steady at the maximum value for a time.
It then falls very rapidly back to zero.
The duration of a pulse can be anywhere from a very long time (days) to a very short time (picoseconds or less).
Pulses do not rise and fall instantaneously but take time (which may be very short).
They are called the RISE and FALL टाईम्स
।If pulses occur one after another they are called a PULSE TRAIN.
The duration time of a pulse is called the MARK.
The time between pulses is called the SPACE.
The relative times are expressed as the MARK/SPACE RATIO.
Mark/space ratios can vary.

Fig. 3 has a 50:50 mark/space ratio.
This is a special case called a SQUARE WAVE.
Fig. 4 is about 1:10
Fig. 5 is about 10:1

Note that the last three waveforms are of the same frequency. All the pulses start at the same instant.