FFT Functions on Keysight 3000T Oscilloscopes
应用文章
The oscilloscope Fast Fourier Transform (FFT) function and other math functions are valuable when working with digital and RF designs. For example, the FFT function in an oscilloscope can quickly highlight the frequency content of signals coupled onto power supply rails. This, in turn, can help pinpoint the source of such noise signals. That’s important because such signals can translate into noise in other parts of the design, cutting signal margins, and potentially preventing the design from moving beyond the prototype stage until the problem is fixed.
An FFT spectral view can also be helpful when looking at RF signals to verify if the proper pulse characteristics or modulation is happening. Time-gated FFTs even further evaluate spectral components of a signal, such as what frequency is present at certain points along RF pulses. Math functions such as a “Measurement Trend” on frequency measurements can quickly verify whether a classic modulation scheme is happening properly, like a linear frequency modulation chirp across RF pulses in a pulse train.
This Application Note will explore a number of these examples and look at practical considerations for making FFT measurements and pulsed RF measurements with an oscilloscope.