BWD MINI-LAB 603B Manual page 25

APPLICATIONS:
5.1
FREQUENCY MODULATION
AND
DE-MODULATION;
The aim
of
this
experiment
is
to
demonstrate
the
production
of a
Frequency Modulated
carrier
and
to
show
a
means
of
de-modulating
the
signal to
reproduce
the original
modulating
signal
Equipment
Required:-
(a)
lx
Model
BWD
603B Mini-Lab
(b)
lx
Model
BWD
6001
Tuned Circuit
(c)
lx
Model
BWD
600D Microphone
(d)
lx
Model
BWD
600N
Loudspeaker
(e)
Various
leads
(f)
lx
O.lpF Capacitor
(g)
lx
560pF Capacitor
The equipment
is
connected up
as
shown below;-
The transmitter section produces
the
F.M.
signal
and
feeds
it
into the
tuned
circuit.
By adjusting the
tuned
circuit so that
the centre frequency of the
F.M.
signal
occurs
on
the slope of the response, o
change
in
frequency
will
result
in
a
change
of level across the tuned
circuit.
The resultant Amplitude
Modulated
signal
is
rectified
by
the
detector diode
(the
R.F.
is
removed by C)
and amplified
by
the
two
amplifiers
where
it
can be heard
in
the loudspeaker
or
seen by
•
an
oscilloscope.
603B
5 -
1