General Principles of Operation
System Description
Source Switcher
The source switcher is used to switch test ports to which the RF signal is supplied from the
source.
Signal Separator
The signal separator consists of directivity couplers that detect input and output signals at
the test ports. On a test port to which a signal is output, the output signal and the reflection
from the DUT are detected as the reference signal (R) and the test signal (T), respectively.
On the other ports, the signal that is transmitted through the DUT is detected as the test
signal (T). All signals are then sent to the receiver.
Receiver
Each signal that is sent to the receiver is first converted into an IF signal by a mixer and
then converted into a digital signal by an ADC (analog to digital converter). These
processes are applied to each signal independently. The digital data is then analyzed by a
micro processor and measurement results will be displayed on the screen.
Appendix E
455