U3042AM04
Service Information
Theory of Operation
The following is a description of the operation of the test set. Reference the test set
block diagram shown in
. This section assumes the user has a
general understanding of couplers, switches, and network analyzers.
The test set adds 4 test ports to a 4-Port network analyzer. The internal RF switches
direct the source and receiver signals of the analyzer to the selected measurement
test port.
The switches and couplers are arranged in four groups to control the source and
receiver paths of the analyzer port to the couplers in the column under the analyzer
port.
Test Set Control Board
The test set Control Board (N5261-60006) is a surface mount, printed circuit
assembly (PCA). It provides a connection to the power supply, and the analyzer’s Test
Set I/O for control of the RF switch paths (through the Switch Interface board
(U3025-60062). The front panel “Active” and port LEDs are on only when the analyzer
has addressed the test set. The rear panel fan is on when the controller board
supplies are operational.
Switch Interface Board
The Switch Interface board (U3025-60062) is installed on top of the test set
Controller Board and provides connections to the RF switches. This board regulates
the DC voltage supply (24 volts), and routes logic signals to the switches.
Front Panel LED Boards
Four LED board assemblies (N5261-60005) are mounted to the front panel. The LEDs
indicate the Source Path (amber/yellow color), or Receiver Path (green colored)
shown as “S” and “R” on the front panel. The LED board assemblies are connected to
the test set controller board.
DUT Control Board
The DUT Control board (U3020-63223) provides eight control lines for controlling an
external device. The DUT Control Board installed on the rear panel and is connected
to the test set Control board through a ribbon cable to J9.
Power Supply
The switching power supply (0950-4729) coverts the AC line voltages to DC. This is
an automatic line voltage selecting power supply. The DC supplies are connected to
the test set control board through four wire harness to J11, J12, J13 and J14. The
9/10 Vdc section of the power supply is not used in this instrument. The AC line
voltage (100 to 240 V @ 50/60 Hz) is provided from the line module on the rear
panel.
RF Coupler/Bridges
The test set uses 4 couplers (5087-7752) on the front panel for RF Test Ports 5 to 8.
The couplers provide the signal separation of the source and receiver paths. The test
set ports can receive from or stimulate a signal to the DUT.
Keysight U3042AM04 User's and Service Guide
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