Long description
This figure consists of two graphs of signal strength against frequency. Each one shows two rectangles of the same height, a narrow one and a much wider one, with the frequency band of the narrow rectangle completely overlapping with part of the frequency band of the wider rectangle. In graph (a), the wanted signal has a wide bandwidth, and narrowband interference overlaps with part of it. In graph (b), there is a broad spectrum of wideband interference, and a narrow wanted signal overlaps with part of it.