HP HP 8712ET, User Manual, Page: 55 / 480

ET User’s Guide 3-3
Making Measurements
Measuring Devices with Your Network Analyzer
Measuring Devices with Your Network
Analyzer
This section provides a basic overview of how the network analyzer
measures devices. The analyzer has an RF signal source that produces
an incident signal that is used as a stimulus to the device under test.
Your device responds by reflecting a portion of the incident signal and
transmitting the remaining signal. If the device is passive, some of the
transmitted signal will be absorbed, indicating a “lossy” device. If the
device is active, the transmitted signal may be amplified, indicating that
the device has gain.
Figure 3-1 shows how a device under test (DUT)
responds to an RF source stimulus.
Figure 3-1 DUT Response to an RF Signal
Refer to Figure 3-2 for the following discussion regarding detection
schemes and modes. The transmitted signal (routed to input B) and the
reflected signal (input A) are measured by comparison to the incident
signal. The analyzer couples off a small portion of the incident signal to
use as a reference signal (routed to input R). Sweeping the source
frequencies, the analyzer measures and displays the response of your
test device.
Figure 3-2 shows the transmitted, reflected, and reference
signal inputs.