Output Standing Wave Ratio (Swr) Test; Specification; Description - Agilent Technologies 4418B Service Manual

Output Standing Wave Ratio (SWR) Test

Specification

Electrical Characteristics
Output SWR
1. For instruments with the 50MHz 1mW output (power ref) connector
mounted on the front panel.
2. For instruments with the 50MHz 1mW output (power ref) connector
mounted on the rear panel. This applies to models E4418B and E4419B
with option 003 fitted.

Description

This test measures the standing wave ratio (SWR) of the 50MHz 1mW
output (power ref) connector on the power meter to verify that it is within
its published specification.
When RF power is transferred from a source to a load, the level of power
absorbed by the load, P
load and the effective output impedance of the source. This can be
expressed in terms of the voltage reflection coefficients (VRC) as follows:
Equation 2-5: Power Absorbed By The Load
Γ
2
1 –
L
×
----------------------------
P = P
A ZO
1 Γ Γ
–
S L
Where:
Where:
• P is the power that the source will deliver to a matched load.
ZO
• Γ and Γ
are the VRCs of the source and load respectively.
S L
This method for measuring the source match exploits this relationship by
presenting the source with two different values of Γ
power delivered to the load under the two conditions. The load used is a
Agilent E4418B/E4419B Service Guide
Output Standing Wave Ratio (SWR) Test
Performance Limits
, is dependent on the respective impedance of the
A
2
Performance Tests
(maximum)
1
1.06
2
1.08
and measuring the
L
2-23