Sinusoids are an extremely important category of time-varying functions (or signals) and are used in many situations: In the electrical power industry sinusoids are the dominant signal used to transfer power. In communication systems (cellular telephones, radio signals, etc.) the so-called carrier signals are sinusoidal. Vibrations in mechanical systems are a common source of failure—the stresses caused by these vibrations are commonly analyzed in terms of sinusoids.

Signals

A sinusoidal sweep is a sinusoid whose frequency varies with time. Sinusoidal sweeps have practical applications in the testing of engineering systems. By applying a sinusoidal sweep to a system, we can measure the system's response to sinusoids of various frequencies. These measured responses can be used to predict the system's response to other inputs.

Signals

Modulated signals are composed of a carrier signal which is modified in some way based on another signal, generally called the baseband signal. The baseband signal refers to the original range of a signal before it is modulated to a different frequency range. Two primary modulation approaches are amplitude modulation and frequency modulation.

Signals

Oscilloscope Triggering

Oscilloscope triggering allows us to assign a “zero time” to a particular feature on the signal. That feature gets placed on the same point on the plot window every time the oscilloscope screen updates; if the signal repeats itself based on this feature, the oscilloscope will display the same section of the signal every time the screen updates, making the signal appear to be unchanging.

Oscilloscope Signals Waveform