Table of Contents
Advertisement
Appendix
Network analyzers—definitions and capabilities
Before discussing the measurements made with a
network analyzer, it is important to have an under-
standing of a network analyzer block diagram and
how analyzer makes measurements.
Network analyzers provide a wealth of information
about a device, including its magnitude, phase, and
group-delay response to a signal. The hardware
inside a network analyzer includes a source for
stimulus, signal-separation devices for measuring
a portion of the incident signal and for separating
signals traveling in opposite directions on the same
transmission line, receivers for signal detection,
and display/processing circuitry for reviewing
results (Figure 11).
Incident
Reflected
Source
Reflected
Incident
(A)
(R)
Receiver/detector
Processor/display
Figure 11. General network analyzer block diagram
Transmitted
DUT
Signal
Separation
Transmitted
(B)
Network analyzers measure a portion of the source
power to use as a reference signal. The remainder
of the signal reaches the DUT where part of the
signal reflects back from the device and part of the
signal transmits through the device. The reflected
signal creates a standing wave consisting of both
forward and reverse traveling waves. The signal-
separation equipment allows for the detection of
each of these waves separately. After measuring
the reflected or transmitted signal, the analyzer
ratios it with the reference signal to measure the
characteristics of the DUT.
23
Advertisement
Table of Contents
