Credit: ccarlstead CC-BY 2.0. Playing cards developed their four-suit design in the 1480s in France. By the late 1800s, factories mass-produced standard English playing cards that featured diamonds, hearts, clubs and spades, a design that prevails as of September 2014. Older cards were based on Latin suits of cups, swords, coins and rods.
Definition - What does Spread Spectrum mean? Spread spectrum is a technique used for transmitting radio or telecommunications signals. The term refers to the practice of spreading the transmitted signal to occupy the frequency spectrum available for transmission.
Spectrum management. Spectrum management is the process of regulating the use of radio frequencies to promote efficient use and gain a net social benefit. The term radio spectrum typically refers to the full frequency range from 3 kHz to 300 GHz that may be used for wireless communication.