Marconi Instruments 2955 - Page 41

OPERATION
@
SCOPE
key,
WTien
selected,
the
single
trace
oscilloscope
display
enables
an exter-
na!
modulation
level
to
be
correctly
set.
(|^
EXT
MOD
INPUT
socket.
BNC
connector for
the
application
of an
external
modu-
lating
signal.
When
added
to
the
internal
modulation, provides two
or
three
tone
modu-
lation.
The
maximum
level
is
then
displayed.
(2^
HELP
key.
Enables
access
to
the
CHANGE
PARAMETERS
menu
for
selection
of
EMF
(unloaded)
or
PD
(loaded).
@
TORIES
key.
Used
to
select
two tone
modulation using the
internal
AF
generator.
RF
generator
operation
Signal
generator
operation
is
detailed
under
frequency,
level
and modulation.
Proceed
as
foUows:-
(1)
'
Select
RX
Q.
RECEIVER
TEST
is written
on
the
screen,
(2)
Select
function
RF
GEN (T)-
(3)
Connect
the
unit
under
test
to
RF
IN/OUT
BNC socket
@
or to
N socket
Press
SELECT
(ij)
until
the
LED
lights
above
the
socket
selected for the
RF Output-
Frequency
To
tune
the
signal
generator
frequency,
proceed
as
follows:-
(4)
Select
FREQ
0
.
The
frequency
to
be changed is
shown in
reverse field.
Enter
the
data
on
the keypad
(T).
ending
with
the
frequency
terminator
0.
e.g.
’
for
123.5
MHz.
enter the
following:-
If
a
mistake
is
made
during
data entry,
press
DELETE
(u)
and
then
enter the
correct
character.
When,
however,
the terminator
0
has
been.
pressed,
re-enter
the
complete
data.
If
incorrect
data
has been
entered,
e.g. a
frequency
outside
the
range
of the
instrument,
the
terminator
is ignored
and the entry
is
not be
accepted.
Use
DELETE
and
then
re-enter
the
data.
(c) If
required,
set
the
frequency
incremenL'decrement
by
selecting
A
INCR
0
)
and
enter
the
data,
ending
with
the frequency
terminator,
e.g.
for 500
kHz steps,
enter
the
foilowinz:-
In
the
example.
FREQ may
be omined
since
it has been
previously
entered
in
(4).
46881-622N
Apr,
88
3-17