How to right-size your wireless testing: Page 4 of 5

July 11, 2016 //By JFW Industries
Whether mobile devices, Internet of Things, or industrial RF applications, the world runs on wireless. As a result, wireless testing is more important than ever before. But how do you balance thoroughness, speed, and budgets? Quipping “pick any two of the three” isn’t a good answer. Testing must be thorough, fast enough to keep up with getting to market, and yet within tight budgets. Test engineers should adopt a right-sizing approach to manage trade-offs and find solutions that are the best fit for a particular situation.

The hub fan-out is the simplest design, using a hub and spoke topology. There is only one programmable attenuator per port. But you sacrifice flexibility. Each radio communicates to every other radio through the test system at the same time.

When you set the attenuator on one port, you’ve now limited its transmission to every other port, rather than independently setting the attenuation for each possible pair of communicating devices. You can still program a specific amount of attenuation between any one pair of radios, but you lose flexible control over the attenuation on all other possible paths.


The example diagram shown is a 12 port hub fan-out configuration. All ports are connected via a resistive power divider/combiner with a star configuration. There are a total of 12 programmable attenuators.


The example diagram shows a 12 port LC8 design. Each port is connected to only its 8 closest neighboring ports (4 upper neighboring ports & 4 lower neighboring ports). This design requires only 48 programmable attenuators.


The example diagram above is a 12 port full fan-out configuration. This 12 port design will have a total of 66 programmable attenuators.

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