Marconi Instruments 2955 - Page 51

OPERATION
(J)
SINAD
S/N
key.
Selects
SIN.AJD
or
signai/noise and
causes
the AP
generator
to
modulate
the
signal
generator with
a 1 kJiz tone.
The display
indicates
when
SIN.AX)
or
S/N
is selected.
SCOPE
key.
Disabled
as
bar charts
only
are displayed in
duplex
mode.
(n)
BAR
CHART
key.
Disabled
as
bar charts are always
displayed
in
duplex
mode.
RX=TX
FREQ
key.
Can
be
used
to set
the RF
generator
to the
transminer
fre-
quency.
When
this key
is
used, it
is
followed
by an increment key which has
been
preset
to
the
appropriate
offset.
Duplex
operation
The
following
procedure
assumes
that
both
the transmitter
and
the
receiver
are
modulated
in
the
same
%vay.
If not,
follow
the procedures
given
under
the
appropriate
transmitter
and
receiver
test
headings.
Proceed as
follows:-
(1)
Press
DUPLEX
Q.
DUPLEX
is displayed together
with
the
current
instru-
ment
settings
under
RECEIVER
and
TRANSMITTER
headings.
(2)
Select
one
pon
operation
by pressing
the SELECT key
(T)
until ONE PORT is
displayed
in
reverse
field
with
the
LED
lit above
socket
(?).
(3)
Select
nvo
pon
operation
by pressing the
SELECT
key (T) until
TWO
PORT is
displayed
in
reverse
field with
both
LEDs
lit.
Additionally,
BNC
and N are dis-
played
in
reverse
field
to indicate
that the connections are the
receiver to BNC
soc.kei
Q
and
the
transmitter
to
N socket
(J)*
(4)
Set the
receiver’s
frequency
and set the
signal generator
frequency,
level and
modulation
(as
under
these
headings in ‘Signal generator
operation’).
Note,
how'-
ever,
that
the
A
INCREMENT
keys (T) are only operable
when the signal
generator
step value
had
previously
’oeen set in
RX
mode. Note also
that
the
maximum signal
generator
output
le\'ei
is
-SO dBm
tor one
port and-
-54 dBm for
two
port
operation.
(5)
Connect
the
receiver
input
to
either the
N
socket (T) for
one port
operation or
to the
BNC
socket
for
two
port
operation.
(6)
Set the
transmitter’s
frequency, level
and
modulation.
(7)
Connect
the
transmitter's
output
to
the
N
socket
(T) for
both
one
and
tw’o pon
duplex
operation.
(8)
Read
the
transmitter's
RF pow'er and .modulation
parameters
from
the display.
Note
that,
for
duplex
mode,
the
bar
chart display
is
required
and
therefore
both
the
SCOPE
@
a.nd
BAR
CHART
(JT)
keys are disabled. Note
also
that
the audio
filter
value
is
displayed
under
the
TX
side
of
the display
but
applies
to
both
TX and
RX
measurements.
46881
-622N
Apr.
88
3-27