The Resolution Revolution In Oscilloscopes

Figure 1: Teledyne LeCroy's WavePro HD exemplifies
today's high-resolution, high-bandwidth instruments

Oscilloscopes have been around for a very long time now, and older oscilloscope users will remember the heyday of those analog boat anchors of the '60s and '70s. Many have survived and are still usable if you don't need much bandwidth (and have the means to calibrate them if necessary). I used to scout local hamfests looking for bargains on them. Many techs and engineers cut their teeth on those behemoths. You could learn a lot about design if you poked around inside them, too.

Which Windowing Function to Use in FFTs?

Figure 1: Examples of a Hamming
function (blue) and Hanning function
(red)

When performing a fast Fourier transform on an acquired waveform, you'll often encounter situations where the waveform doesn't sit neatly within the oscilloscope's acquisition window so that the voltage is the same at the window's beginning and end. The ensuing discontinuity from window to window results in high-frequency artifacts, and the way to address this issue is a technique known as "windowing."