The sampling oscilloscope as a microwave instrument

Many modern high-speed oscilloscopes are well suited for precise measurements of microwave waveforms, modulated signals, and nonlinear phenomena. These oscilloscopes are flexible, easy to use, and relatively inexpensive, which makes them ideal for testing a wide variety of microwave sources and other microwave components. High-end real-time oscilloscopes circumvent the bandwidth of 500 MHz limitation by embedding the sampling circuitry in a 50-μtransmission line terminated in a 50-μ load. The switches in a sampling oscilloscope are typically constructed with fast sampling diodes and are opened and closed by fast electrical strobe pulses. Synchronized timebases in an oscillator uses an oscillator locked to, and slightly offset from, a reference signal from the source. High-speed sampling oscilloscopes often greatly speeds troubleshooting and lends itself to the development of an intuitive feel for what is going on in a circuit.