Anritsu ME7840A - Manual (Page 18)

q Bandwidth: Should be sufficiently wide to cover the frequency band
of the AUT.
q Isolation: Should be no less than (P
o
-27 dB), where P
o
is the
power output in dBm of the AUT. Thus for Po = 47 dBm (50 watts),
a 20 dB isolation is required. For a P
o
greater than 47 dBm up to 50
dBm (100 watts), two circulators in series can be used.
Where S
22
or Hot S
22
measurements are not required, power amplifiers
with up to 100 watts average output power can be tested with the
MS4782D Test Set without any circulator by connecting the through arm
of the output coupler directly to the 100 watt termination (Port C1 con-
nected to Port C2 on the rear. The unit is shipped from the factory with
this loop jumper.)
For S
22
measurements, the transfer switch located within the Scorpion
routes the source 1 output signal to the output port of the AUT via Port 2
(RF2) of the Scorpion. A separate 100-watt coupler in the test set applies
the –30 dB portion of this incident signal to the Scorpion reference port
a
2
. The –30 dB portion of the signal reflected from the AUT output port is
applied to the Scorpion test port b
2
by means of the AUT output coupler.
The PATS calibration is performed with the test set in place, at the con-
nectors where AUT will be connected directly. Therefore, the test set com-
ponents and cables are included in the calibration loop and their effects
are calibrated out, resulting in correct and accurate measurements of the
AUT.
The software supplied by ANRITSU supports operator control of the
source selection switch and step attenuator in the test set. This control is
achieved through the parallel TTL control lines available at the Scorpion
rear panel “External I/O” connector. The GPIB commands from the PC to
the Scorpion set the TTL control lines to the desired states.
Connectors and
Ports On the front panel of the Model MS4622/3C DRA Scorpion three Type N
(female) connectors are provided for Ports 1, 2 and 3.
Port 1 provides RF source 1 when the transfer switch is in the forward
position, and is terminated in 50 ohms to ground when the transfer
switch is in the reverse position.
Port 2 provides RF source 1 when the transfer switch is in the reverse po-
sition, and is terminated in 50 ohms to ground when the transfer switch
is in the forward position.
Port 3 is allocated to RF source 2. Under independent control, port 3 pro-
vides RF source 2, or is terminated in 50 ohms to ground.
On the rear of the unit, four SMA connectors (Figure 1-4) are provided for
Reference ports a
1
and a
2
and Test Ports b
1
and b
2
. The front of the unit
as well as all other mechanical specifications is the same as the model
MS4623B.
On the MS4782D Test Set, three additional SMA connectors provide for
connecting an external circulator. If reverse measurements (S
22
and Hot
GENERAL INFORMATION SYSTEM DESCRIPTION
ME7840A OMM 1-7
CAUTION
Connecting the external
circulator incorrectly or
placing a direct connection
between C1 and C3 on
MS4782D rear panel will
cause permanent damage
to MS462XC.