Operation
R&S
®
OSP
147
User Manual 1178.7100.02 ─ 05
4
Operation
Here is an overview of using the R&S
OSP and various interaction methods.
How to Work with a Switch Unit
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Operation in Interconnection Mode
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4.1
How to Work with a Switch Unit
The application-specific switch modules of the R&S
OSP facilitate tests by automati-
cally switching the required RF signal paths during measurements. Automatic path
switching is a much preferred alternative over having to rearrange coaxial cable con-
nections repeatedly, for example, in RF test systems.
For example, many EMC tests comprise scans across frequency ranges that require
using two or more different transducers consecutively. Without a switch unit, you must
unscrew the cable connector of the first transducer from your test instrument, once
reaching the end of the first part of the frequency range. Then you must connect the
cable of the next transducer, which is capable of measuring in the next part of the fre-
quency range. Repeating the scan with the next DUT requires changing the connection
again, and so on. This procedure is time-consuming, error-prone, and causes signifi-
cant wear on all connectors involved.
A switch unit takes care of changing the RF connections by dedicated relays. For an
alternating connection of two transceivers, for example, to one test port of a measure-
ment instrument, you can use an SPDT relay module in the switch unit. Connect the
first transducer to the relay's NC terminal port, the second transducer to the NO termi-
nal port, and the test instrument to the common terminal port. During a frequency scan,
your test control software can let the relay switch from NC to NO in the right instant.
Hence, all connectors remain screwed in place, while the relay does the switching.
Figure 4-1: Example of a basic setup with one switching function, only
1
= Transducer 1, for example, a log-periodic antenna that covers 80 MHz to 6 GHz
2
= Transducer 2, for example, a horn antenna that covers 1 GHz to 18 GHz
3
= SPDT relay (single-pole double-throw switch)
4
= Test instrument, for example, a receiver that covers 10 Hz to 26 GHz
How to Work with a Switch Unit
