Marconi Instruments 2955 - Page 25

Chapter
3
OPERATION
Foilowing
power-up
conditions
and
a
summary
of
the
front and
rear pane!
controls
and
connectors,
each
of the
main
functions
of the
instrument
is separately
detailed
in
this
chapter.
The
main
functions
are
arranged
under
the
headings
of transmitter
testins,
receiver
testing,
duplex
testing
and
tones
decoding
and
encoding.
Additional
operatins
information
is
provided
upon
pressing
the
HELP
key;
details are
given
under
‘HELP
Key
Operation
.
To
obtain
familiarity
with
the
instrument,
foilow
the
operating
sequences
given
under
‘AF
Generator
Operation'
and
‘Signal
Generator
Operation';
these
involve
detailed
keyboard
operations
for
transmitter
and
receiver
testing
respectively.
INITIAL
SETTINGS
~
When
switched
on,
the
instrument
automatically
enters
and
displays
the
following
set
conditions:-
Conditlon
Mode
RF
generator
frequency
RF
generator
level
Modulation
frequency
Modulation
level
Filter
Connector
SELF
TEST
^
At
any
time,
following
a
period
after
switch-on
to allow the frequency standard to
stabilize
(typically
5 minutes),
the
instrument
may
be
self-tested. This
faciiity is entered
using the
HELP
key.
Operating
details
are given
under
‘HELP
Key Operation’.
Setting
RX
300 MHz
-100
dBm
1
kHz
FM
1.5
Hz
0.3-3.4
Hz
N
socket
SELECTING
MEASUREMENT
MODE
Once the
instrument
displays
its initial
settings,
you can
select
the
required
measure-
ment,
usually
in
three
steps
as follows:-
(1)
Select
mode,
e.g.
TX,
RX,
Tones
-
BLLTE key.
(2)
Select
function,
e.g.
AF
Gen.
Sec Modulation-
GREEN
key.
(3)
Enter
data
for
frequency,
level
etc
-
ORANGE
and
WHITE
keys.
Changing
from
one
measurement
to another
is
by simple
key
operation.
For
details
of the
use
and
operation
of the
controls
for each
measurement,
see
under
the
relevant
heading,
e.g.
to
measure
transmitter
pow'er,
see under
‘RF Power
Meter.
46881
-522N
Apr.
S3
2-1