An oscilloscope cannot be used to:

An oscilloscope displays signal amplitude versus time. While it can easily show complex voltage waveforms, measure frequency (by calculating the period), and measure DC voltage, it is not designed to directly measure FM carrier deviation. Frequency Modulation (FM) changes the frequency of the carrier rather than the amplitude. Because an oscilloscope shows amplitude variations over time, small frequency changes (deviation) are incredibly difficult to isolate, see, or measure accurately on a standard time-domain display. To measure FM carrier deviation, specialized instruments like a deviation meter or a spectrum analyzer (which operates in the frequency domain) are typically used instead.