Years ago, an oscilloscope was not the first instrument an RF/microwave engineer would reach for when troubleshooting or analyzing high-frequency circuits. But as semiconductor devices and circuit technologies have evolved, the line between what is high frequency and what is high speed has blurred just as it has between what is considered an analog device and what is called a digital device. In many cases, wireless receiver modules, for example, contain both analog RF/microwave front-end components as well as analog-to-digital converters (ADCs) and microcontrollers.
Oscilloscopes are now made with wider bandwidths than before and with phenomenal bandwidths and sampling rates, reaching as high as 100 GSamples/s in the latest instruments, which can capture even the most elusive glitch or transient event. While it may lack the simplicity and universal ease of use of a voltmeter, an oscilloscope is about as invaluable on the test bench, and has come to take its place alongside many traditionally "microwave" signal analysis instruments, such as spectrum analyzers, scalar network analyzers (SNAs), and vector network analyzers (VNAs). In fact, many engineers now are beginning to wonder how they ever managed in the past without their oscilloscopes. The summaries that follow point to several articles that offer insights into the use of a scope for high-frequency analysis.