The phrase "narrow band" refers to something that is small or limited in width or range.
Sentences with «narrow band»
Colors consists of narrow bands of colour sliding across a screen while (at least in the bit I experienced) fragments of pop pulse on the soundtrack. (theguardian.com)
Since 2011, lawmakers have disclosed their outside earnings within narrow bands, but lawyer - legislators do not need to list their clients. (politico.com)
The heart of a jet stream is a relatively narrow band of strong wind a few hundred miles wide that can reach speeds of more than 200 miles per hour. (discovermagazine.com)