Specifications

The forward or reverse stimulus signals are sampled by the reference sig
-
nal sampling couplers and are then sent to a SP3T switch. In the
MS462XB, the Port 3 reference signal that is input via J5 is also sent to
this switch. In the MS462XD, the Port 3 or Port 4 reference signal from
the second ARM is also sent to this switch.
This SP3T switch selects the proper Port reference signal to be output via
J3, depending on sweep direction and test port used. The signal from J3 is
used by the Down Conversion Module as a reference signal. In the
MS462XD, a second Auto-Reversing Module is used to distribute the
stimulus signal from the second source module to the Port 3 and Port 4
modules. The ALC Leveling Coupler’s DC output signal is used by the
ALC circuits located in the second source module.
Non-Reversing
Module
The Non-Reversing Module contains the ALC leveling coupler and cou
-
pler providing two signal paths. The signal input port is J4. The output
signal from J1 goes to the Port 1 Module providing the stimulus signal for
the DUT. The signal from the coupled port, J3, is used by the Down Con
-
version Module as the Reference signal.
Step Attenuator The Step Attenuator isa0to70dBattenuator that provides attenuation
in 10 dB increments.
Port Module The Port 1/2 Module contains a directional coupler and an integrated bias
tee.
Port 3 Module The Port 3 Module contains a directional coupler, an ALC leveling coupler,
the Port 2/Port 3 test signal switch and a coupled port for the source sig-
nal.
The signal input port is J2. The output signal from J3 goes to J1 via the
Step Attenuator (if equipped). The Port 2 test signal is input to J6. The
internal switch selects the test signal to be output via J5, depending on
the Port used. The signal from J5 is used by the Down Conversion Module
as the Test signal. The signal from J4 is the sampled Port 3 Reference sig
-
nal and is routed to the Down Conversion Module via J5 of the
Auto-Reversing Module.
Low Noise
Pre-Amplifier
This Pre-Amplifier provides a minimum gain of 16 dB (up to 6 GHz) with
a Noise Figure of less than 3 dB.
Switched Module The Switched Module contains a bi-directional SPDT switch.
High Isolation
Switch Module
This SPDT switch multiplexes the test signals from Port 3 and Port 4 to
the Down Conversion Module.
Receiver Module
Configurations
There are 20 possible front end configurations of the Receiver Module,
depending on the model and installed options. Refer to the block
diagrams at the end of this chapter.
2-16 MS462XX MM
FRONT END RF COMPONENTS THEORY OF OPERATION