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.
However, for mission-critical applications, particularly those employing commercially available radios, spread-spectrum radios do not intrinsically provide adequate security; ...just using spread-spectrum radio itself is not sufficient for communications security. Resistance to fading.