
42-1
Frequency is the rate of occurrence of a repetitive event. If T is the period of a repetitive event, then the
fr
equency
is it
s
re
ciprocal,
f = 1/T. e In
ternational
Sy
stem
of Un
its
(S
I)
st
ates
th
at
th
e
pe
riod
sh
ould
be ex
pressed
in se
conds
(s
),
an
d
th
e
fr
equency
sh
ould
be ex
pressed
in he
rtz
(H
z)
. e fr
equency
of el
ec-
trical
sig
nals
is o
en
st
ated
in un
its
of ki
lohertz
(k
Hz),
me
gahertz
(M
Hz),
or gi
gahertz
(G
Hz),
wh
ere
1k
Hz
eq
uals
on
e
th
ousand
(1
0
3
) events per second, 1 MHz equals one million (10
6
) events per second,
an
d
1G
Hz
e
quals
o
ne
b
illion
(
10
9
) events per second.
Fr
equency
me
trology
r
st
be
came
a to
pic
of in
terest
ar
ound
19
20,
wh
en ...