Keysight DAQ970A Guia Del Usuario página 264

4 Measurement Tutorials
RF Signal Multiplexing
A special type of multiplexer is the RF multiplexer. This type of multiplexer uses special components to maintain a 50
Ω 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 DAQM905A (50 Ω) 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. Note that
DAQM905A module do not automatically terminate open channel.
264 Keysight DAQ970A/DAQ973A User's Guide