The story behind this piece
Oscilloscopio is the display of a digital oscilloscope, and every reading on it agrees with the traces. At 500 µs/div the 1.000 kHz sine spans two divisions per cycle, the 500 Hz square four and the 400 Hz sawtooth five. The square wave's edges are modelled as a damped second-order response: the zoom window at 50 ns/div shows its 25.4 % overshoot and 29.1 ns rise time, the same figures listed under Measurements. Alongside, XY mode draws Lissajous figures x = sin(a·t + δ), y = sin(b·t) for frequency ratios 1:2, 3:2 and 3:4, the patterns engineers have long used to compare two frequencies by eye.
