if two vibration components are quite close together in frequency and if they are present at the same time at the same place, they will combine in such a way that their sum will vary in level up and d [..]

Where two cyclic components are close together in frequency they combine in such a way that their sum will vary in amplitude at a rate equal to the difference in frequency between the two components. [..]

A periodic variation in a signal resulting when two signals of unequal frequencies are combined. Where the beat is maximum the signal and the samples line up perfectly and the resolution is high. But [..]

The frequency produced when two signals are mixed or combined. The beat frequency equals the difference or offset between the two frequencies. The difference between the oscillator frequency and the u [..]