Oscilloscopes are among the most widely used instruments in the field of electronic test and measurement. To observe the waveform of the signals, it is impossible to do without them. The oscilloscopes are now all color screen and some models have a touch screen. Each oscilloscope manufacturer offers a wide range of models that differ in their bandwidth, acquisition speed, memory depth, the number of inputs and the variety of digital processing, bus triggering and decoding options. The entry-level oscilloscopes display a frequency band of a few tens of MHz while it reaches a hundred GHz for the most high-end. In recent years, digital inputs (8 to 16 in general) have been added to the traditional 2 to 4 analog inputs.