Saluki S3602 Series, User Manual

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8.
Basic Knowledge of Network Measurement
This chapter introduces the following contents:

Reflection measurement

Phase measurement
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Amplifier parameter specifications
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Complex impedance

Group delay
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Absolute output power
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AM-PM transformation
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Linear phase offset

Reverse isolation

Small signal gain and flatness
8.1.
Reflection Measurement
Reflection measurement is an important part of network measurement. At first, the reflection measurement will be introduced. In order
to better understand reflection measurement, the optical wave is applied to simulate the traveling wave transmission along the
transmission line.
If any optical element such as the lens is set, part of light will be reflected by the lens, but the majority of light will be transmitted
continuously through the lens. If the surface of the optical element is a mirror, the majority of light will be reflect, and only a little light
will be transmitted or no light will be transmitted.
1 . Incident light 2. Reflected light 3. Transmitted light
Fig. 8.1 Light Reflection and Transmission
The RF signal will be reflected if the impedance of two connectors is different from each other. Reflection measurement is a process to
measure the ratio of the reflected signal and incident signal. The incident signal is measured by Receiver R, and the reflected signal is
measured by Receiver A. Therefore, the result of reflection measurement is a ratio of A and R (i.e. A/R). The reflection characteristic of
the tested device can be fully quantified with the signal amplitude and phase information of Receiver A and R. Among the S-parameter
terms, S11 represents the reflection of Port 1 (input port) of the tested device and S22 represents the reflection of Port 2 (input port) of
the tested device. Reflection measurement aims to ensure the efficient transmission of RF energy. If energy is reflected, only a little
energy will be transmitted to the expected place. In addition, if too much energy is reflected, the device may be burnt, such as the
output power amplifier.
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Reflection measurement expression

Summary of reflection measurement expression
8.1.1.
Reflection Measurement Expression
The data of reflection measurement can be expressed in various methods according to the requirements. Various expressions are