Schrödinger's Cat in Your Signal Analyzer?

2021-12-01  |  3 min read 

In 1935, a thought experiment was devised by Erwin Schrödinger about whether the act of observing an event affects the state of the subject (in this case, a cat). More broadly, this is a phenomenon known in physics as the Observer Effect. Every seasoned engineer knows not to use a regular DMM to measure the quiescent current of a low power device. The burden voltage affects the circuit sufficiently such that the measurements are no longer accurate. All electronic instruments are affected by this in varying degrees but in the world of mmWave (5GNR, Ka, V-band, etc.) this effect is greatly magnified by a multitude of factors. Why does mmWave pose such challenges? What can be done to mitigate the problems? Let’s explore these ideas and more.

Making accurate measurements in the mmWave regime starts with selecting the right Keysight instrument for the application. The next challenge is to ensure that the internal settings of the instrument and the test network are optimized for (a) path loss, (b) wideband noise, and (c) frequency response. Some of these factors can be corrected by configuring the instrument with a carefully selected attenuation, amplification, and preselector. If all this is beginning to sound hard, Keysight makes it easy by offering the “Optimize EVM” function, which intelligently automates this process.

Whether it’s through a cable or free space, path loss is the bane of RF engineers. In both cases, the loss grows exponentially with the carrier frequency which partly explains why making measurements at mmWave frequency can be difficult. At Keysight, we offer many solutions to mitigate path loss, wideband noise, and frequency response so that you can focus on testing your product.

If you’d like to learn more, please join our webinar, Tackling Your Millimeter-Wave Signal Analysis Challenges, where you’ll discover many innovative and practical solutions.

In case you’re wondering, the cat is doing fine.