And it seemed that a greater range of frequencies imposed on top of one another, a greater “bandwidth,” was needed to generate the more interesting and complex waves that could carry richer information. To efficiently carry a phone conversation, the Bell network needed frequencies ranging from about 200 to 3,200 hertz, or a bandwidth of 3,000 hertz. Telegraphy required less; television would require 2,000 times more. Nyquist showed how the bandwidth of any communications channel provided a cap on the amount of “intelligence” that could pass through it at a given speed.
