Not only is the shape of the waveform important in determining the
amplitude of the frequency components within the Fourier series expansion, but the width
of the data pulses also plays an important role.
As can be seen here, reducing the width of the pulse but keeping the period of the
waveform constant results in an increase in the level of the higher harmonics at the
expense of the lower harmonic levels. Overall, the energy content in the waveform has also
gone down and so the combined power of the harmonics must also be reduced.
In the limit, as the pulse width tends to zero, that is, a delta function, we can expect
the amplitude of each harmonic to approach a constant yet diminishing value.
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