Interesting example of Aliasing. The HAAS Effect! Demonstration (use headphones) Sound Waves and their Sources (1933) Standing Wave in Pipes. Fundamental frequency. The fundamental frequency, often referred to simply as the fundamental, is defined as the lowest frequency of a periodic waveform. In terms of a superposition of sinusoids (e.g. Fourier series), the fundamental frequency is the lowest frequency sinusoidal in the sum.
In some contexts, the fundamental is usually abbreviated as f0 (or FF), indicating the lowest frequency counting from zero.[1][2][3] In other contexts, it is more common to abbreviate it as f1, the first harmonic.[4][5][6][7][8] (The second harmonic is then f2 = 2⋅f1, etc. In this context, the zeroth harmonic would be 0 Hz.) All sinusoidal and many non-sinusoidal waveforms are periodic, which is to say they repeat exactly over time. Where x(t) is the function of the waveform. This means that for multiples of some period T the value of the signal is always the same. Where f0 is the fundamental frequency and T is the fundamental period. F0leftclosed F0rightclosed Therefore, using the relation F0bothclosed F0bothopen See also[edit]