Marconi Instruments 2955 - Page 30

OPERATION
(T)
DELETE
key.
Deletes a
preceding digit, decimal point or minus
sign entered
on
(T).
VARIABLE
control.
Analogue control
which varies
the smallest
increment
of the
function
data.
Step
size
is independent
of
(a)
and
depends upon range.
The
level
or
frequency
assignment
is
shown
in reverse
field on the
screen.
(JT)
A INCREMENT
keys.
Implement the increment (up
arrow)
key and decrement
(down
arrow)
key
in
frequency
or
level
in the step size set
using
@
AF GEN
OUTPUT
socket.
BNC
connector
supplying
an
output in the
range
20 Hz
to
20
kHz
for
single
tone
operation
plus
a fixed 1 kHz for
two
tone operation. Impedance
5
Cl.
AF
INPUT
socket.
BNC socket for
the optional 600 dBm accessory.
(2)
HELP
-key.
Used to select the
20 dB
attenuator and 600
dBm accessory as des-
cribed
under
‘KELP Key
Operation’.
(Ti)
TONES
key.
Used to select two
tone
operation.
AF generator
operation
AF
generator
operation
is
detailed
under frequency
and
level.
(1)
Select
mode
TX
(T).
TRANSMITTER TEST is
wrinen
on
the
screen.
(2)
Select
function
AF GEN
(T)
GEN
is
shown in
reverse
field
on
the
screen.
(3)
Connect
the
unit under test to the .AF GEN
OUTPUT
socket
(J^.
(4)
To
use
the
optional 600 Cl dBm
accessory,
e.g.
for
testing
telephone
lines,
connect
this
unit
between
AF
GEN
OUTPUT
@
and
the AF
INPUT
@
sockets.
To
change
the
.AF voltage
readings to dBm
(into 600 O) use
the
’Change
Parame-
cers’
function.
When
this is
selected,
dBm
appears in
place of
voltage.
The
acces-
sor\’ also
provides
a
20
dB
attenuated
output
which
is also
selectable
in
the
‘Change
Parameters’
function. W’nen
this option is
seiecred,
a
reverse
video
.A
is
displayed.
Frequency
To
tune
the
AF
generator
frequency,
proceed
as
follows:-
(5)
Select
FREQ
(T). The frequency
to
be
changed
is
shown
in
reverse
field.
Enter the
data
on
the
keypad
ending with
the
frequency
terminator
e.g.
3-6
46881
-622N
Apr.
88