
40-6 Electromagnetic Variables
warn the operator. In any case, never forget that pulsed signal, in particular even when repeated with
ve
ry
l
ow
d
uty
c
ycles,
c
annot
b
e
r
epresented
w
ith
delity
b
y
a f
requency
s
wept
s
pectrum
a
nalyzer
.
e kn
owledge
of th
e
no
ise
o
or
le
vel
al
lows
a go
od
va
luation
of th
e
no
ise
te
mperature,
T
n
(and there-
fore
of th
e
se
nsitivity),
of th
e
an
alyzer,
a us
eful
pa
rameter
on ma
ny
oc
casions
. e re
lations
in
volved
ar
e
a
s
f
ollows
.
e N
yquist
r
elation
s
tates
t
hat
P k T B= × ×
n
(40.1)
where
P
i
s
t
he
n
oise
oor
p
ower
l
evel
r
ead
o
n
t
he
d
isplay
(
W)
k
i
s
t
he
B
oltzmann
c
onstant
= 1.38 × 1
0
−23
(J/K)
B
i
s
t
he
p
assband
o
f
t
he
s
elected
I
F
(
Hz ...