RF Signal Multiplexing
A special type of multiplexer is the RF multiplexer. This type of multiplexer
uses special components to maintain a 50Ω or 75Ω impedance in the
signal line being switched. In a test system, these switches are often
used to route a test signal from a signal source to the device-under-test.
The switches are bi-directional. The diagram below shows two examples
of a 4-to-1 channel RF multiplexer in a test system.
By using patch cables, you can expand RF multiplexers to provide
additional test inputs or outputs. For example, you can combine two
4-to-1 multiplexers to create a 7-to-1 multiplexer as shown below.
On the 34905A (50Ω) and 34906A (75Ω) RF multiplexers, you can close
only one channel per bank at a time; closing one channel in a bank will
open the previously closed channel. These modules respond only to the
CLOSE command (OPEN does not apply). To open a channel, send the
CLOSE command to another channel in the same bank.
Signal
Generator
4 x 1 Multiplexer 4 x 1 Multiplexer
Test 1
Test 2
Test 3
Test 4
External
Power Meter
Source 1
Source 2
Source 3
Source 4
Oscilloscope
Test 1
Test 2
Test 3
Patch Cable
Test 4
Test 5
Test 6
Test 7
4 x 1 Multiplexer
4 x 1 Multiplexer
Chapter 8 Tutorial
RF Signal Multiplexing
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