Long description

This figure consists of two graphs with a double-headed arrow in between them.

The graph on the left shows signal value against time. It is made up of a large number of vertical lines extending from the horizontal axis. If you were to join the ends of the lines, the shape would be a symmetrical curve consisting of a tall central peak with much smaller lobes on each side, alternating below and above the horizontal axis, and reducing in height the further away they are from the centre. This shape is known as the sinc pulse.

The graph on the right shows spectrum against frequency. It starts as a horizontal line close to 0, then rises vertically to a new value, where it stays for a certain range of frequencies before descending vertically back to nearly 0. The overall shape is that of a rectangle.