Specifications
SAMPLE
RATE:
50
kHz
SPECTRA
AVGD:
1
MAGNITUDE
SCALING:
volts
e)
Change
the
signal
output
of
the
Wavetek
132
to
a
sine
wave.
Construct
the
envelope
detector
shown
in
Figure
2.
+
N4764
HX-
Vn,
M
#
_
10
KQ
Figure
2
Split
the
AM
signal
output
(from
the
Wavetek
186)
and
apply
it
the
input
of
the
envelope
detector.
Read
the
voltage
across
the
20
KQ
resistor
and
send
this
signal
to
DOP
channel
C.
Channel
C
is
the
demodulated
signal.
Compare
this
to
the
input
signal.
Adjust
the
variable
attenuation
on
the
Wavetek
186
for
100%,
<100%
and
>100%
modulation
obtaining
plots
for
each
case.
Q:
Using
the
crosshairs
on
the
RAPIDS
system,
measure
the
modulation
index
for
each
case.
How
does
this
effect
the
output
of
the
envelope
detector?
Q:
Compute
and
draw
the
spectra
of
the
modulated
sine
wave.
View
and
plot
the
spectrum
of
the
AM
signal
at
each
instance.
Q:
What
effect
does
the
modulation
index
have
on
the
spectra
of
each
signal?
Lab
3
Page
4
59