#### Example 1.1 Example 1.2 Example 1.3 | #### Question 1.1 Question 1.2 Question 1.3

## Spectrum of a periodic data pulse train

#### If we now consider the Fourier series expansion of a train of pulses representing successive data bits, we find (see examples) that the amplitudes of the frequency components are all constrained by a general spectral envelope which passes through zero at multiples of the data pulse width t. |
#### This spectral envelope is given by the equation: #### #### which is usually termed the sinc function. |