Specifications

Analyzer
Module
The analyzer module down-converts, receives, and
interprets the IF signal for phase and magnitude
data. It then displays the results of this analysis on
a color display. This display can show all four
S-parameters simultaneously. In addition to the in
-
stalled display, you can also view the measurement
results on an external color monitor.
3-3 NETWORK ANALYZERS We will begin this discussion with a subject familiar to most Anritsu
customers: scalar network analysis. After showing comparisons, we
will proceed to the fundamentals of network analyzer terminology and
techniques. This discussion serves as an introduction to topics
presented in greater detail later in this section. This discussion will
touch on new concepts that include the following:
q
Reference Delay
q
S-parameters: what they are and how they are displayed
q
Complex Impedance and Smith Charts
Scalar
Analyzer
Comparison
Network Analyzers do everything that scalar ana-
lyzers do except display absolute power. In addition,
they add the ability to measure the phase character-
istics of microwave devices and allow greater
dynamic range.
If all a Network Analyzer added was the capability
for measuring phase characteristics, its usefulness
would be limited. While phase measurements are
important in themselves, it is the availability of this
phase information that unlocks many new features
for complex measurements. These features include
Smith Charts, Time Domain, and Group Delay.
Phase information also allows greater accuracy
through vector error correction of the measured
signal.
First, let us look at scalar network analyzers
(SNAs). SNAs measure microwave signals by con
-
verting them to a DC voltage using a diode detector
(Figure 3-3). This DC voltage is proportional to the
magnitude of the incoming signal. The detection
process, however, ignores any information regarding
the phase of the microwave signal.
In a network analyzer, access is needed to both the
magnitude and phase of a microwave signal. There
are several different ways to perform the
measurement. The method Anritsu employs is to
down-convert the signal to a lower intermediate
NETWORK ANALYZERS, NETWORK
A PRIMER ANALYZERS
MS462XX OM 3-5
SCALAR NETWORK ANALYZERS
MICROWAVE
SIGNAL
MICROWAVE
DETECTOR
DETECTOR
OUTPUT
VOLTAGE
DETECTOR OUTPUT VOLTAGE IS PROPORTIONAL
TO SIGNAL AMPLITUDE.
Figure 3-3. Scalar Analyzer
Detection