Marconi Instruments 2955 - Page 40

OPERATION
A
INCR
key.
Precedes
a
keypad
(?)
entry
so that the
entered datahs
recognized
as
an
increment/de
ere
mem.
(
9
)
DATA
keypad.
For data entry using
numerals
0
to
9,
decimal point and
minus
sign.
(
1
^
FREQ/LEVEL
keys.
For
defining units
of
frequency or
level.
Unless
entering
modulation,
terminates
the data
entry.
@
MOD
FM
key
and LED.
Enables the preceding
frequency
entry
to
be recognized
as
a frequency
modulation deviation.
Activates the
frequency
modulator for the
signal
generator.
LED
lights to show
that FM has been
selected.
Modulation is
switched
on
and off
by
@
MOD
AM
% key
and
LED.
Enables
the preceding
keypad
@
entry
to
be recog-
nized
as an
amplitude
modulation percentage. Activates the amplitude
modulator
for the
signal
generator.
LED lights
to
show that
,AM has been selected.
Modulation
is
switched
on an
off
by'
(^.
'
(?)
MOD
<t»M RAD
key and LED.
Enables the preceding
keypad
(?)
entry to be
recognized
as
a phase
modulation deviation.
Activates
the
frequency
modulator
with
pre-emphasis
for
the signal
generator.
LED lights to
show that
OM has been
selected.
Modulation
is
switched
on and off
by
.
(u)
DELETE
key.
Deletes a preceding
digit,
decimal
point or minus
sign
entered on
the
keypad
(^.
((^
VARIABLE
control.
Analogue
control
which
varies the
smallest
increment
of
the
function
data.
Seep
size
is independent
of
(^
and depends
upon
range,
Tne
level for
frequency
assignment
is
shown in
reverse
field on
the
screen.
(?)
A INCREMENT
keys.
Implement the increment
(up
arrow) key or
decrement
(down
arrow)
key in
frequency
or level
in the step size set using
(?).
0
SELECT key
and
LEDs.
For selecting RF IN/OUT
soc.ket
0
or
0.
LED
lights
above the
socket
selected.
RF IN/OUT
5NC
socket.
For
RF signal
generator
output
levels up
to
225
mV.
Impedance
50 Q.
Automatically
protected
against
excessive
reverse
power
during
duplex
operation.
(0
RF IN/OUT
N
socket.
For
RF signal generator
output levels up
to
22.5
mV.
Impe-
dance 50
n.
0
MOD
ON-OFF
key.
Switches
the signal
generator
modulation,
both
internal
and
external,
on and
off.
Does not affect
LEDs
0
to
0.
0
AF
INPUT
socket.
BNC
socket
used to set up an
external
modulation
level.
3-16
46881-622N
Apr. 88