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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 times.
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.
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