1
\$\begingroup\$

The task is to test multiple DUT's (sequentially) for Transmitter & Receiver testing in multiple unlicensed frequency bands supported by the DUT. I could connect a single RF Signal Generator to 2 DUT's either using a 2:1 Power Splitter or an SPDT RF Switch.

I understand that Port Isolation for Power Splitter is usually lower (~30dB?) compared to an RF Switch (~90dB?) between the 2 output ports. But I am curious (assuming all the ports are well terminated with 50 ohms attenuators), which would be a preferred way to test a particular DUT at a time?

I also understand the RF Switch + Controller assembly could be expensive, but I am trying to understand the application differences between the 2, accuracy-wise, or understand does the comparison even make sense.

The setup is fairly straigh forward, VSA/VSG connected to 2 to 1 splitter/combiner OR SPDT switch which is connected to 2 DUTs. Its a 2.4/5 GHz 802.11 abgn signal, testing Rx signal at -70 dBm sensitivity PER test and Tx signal at 20 dBm power level to measure Power & EVM. Again this will sequential test, where DUT1 gets tested first followed by DUT2.

Improve this question
\$\endgroup\$
4
  • \$\begingroup\$ It would depend on what tests and need for crosstalk rejection of leakage RF. Rx is likely ok but Tx would have to be Mux'd by some digital method. I presume you may have some self tests for Rx but Tx may need shared Analyzer for impedance, spectral response etc. \$\endgroup\$ – Tony Stewart EE75 Mar 6 '17 at 3:11
  • \$\begingroup\$ We could be able to help if your shared some additional information about your test setup, frequency bands, power levels and measurements to be done. \$\endgroup\$ – Enric Blanco Mar 6 '17 at 8:43
  • \$\begingroup\$ The setup is fairly straigh forward, VSG connected to 2 to 1 splitter/combiner OR SPDT switch which is connected to 2 DUTs. Its a 2.4/5 GHz 802.11 abgn signal, testing Rx signal at -70 dBm sensitivity and Tx signal at 20 dBm power level to measure Power & EVM. \$\endgroup\$ – eecs Mar 6 '17 at 15:22
  • \$\begingroup\$ I would imagine that acceptable loss from the signal generator to the DUT is specified by the relevant ETSI standard. Start there. \$\endgroup\$ – Lundin Mar 6 '17 at 15:58
1
\$\begingroup\$

High isolation RF switches are expensive and mechanical switches have finite lifetimes. Also, there is the time involved in switching. If you can use a splitter, you avoid the limited lifetime and time delays.

Improve this answer
\$\endgroup\$
1
  • \$\begingroup\$ Thanks for the pros & cons. Any comments on accuracy wise? \$\endgroup\$ – eecs Mar 9 '17 at 6:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.