RF amplifiers are devices that accept a varying input signal and produce an output signal that varies in the same way as the input but has larger amplitude. The input signal may be a current, a voltage, or any other signal; the output signal is usually of the same nature. They incorporate features including operating frequency range, gain, and output power. The operating frequency range is the frequency range for which the amplifier will meet all guaranteed specifications. Some systems come with features like noise figure, input VSWR, and MMIC technology. The low noise figure indicates better performance. The noise figure value sets the lower limit of the dynamic range of the amplifier. High power RF amplifiers are ideally suited for high power communication systems (like PCs, CDMA, GSM or WCDMA cellular phone base stations), military communication systems, medical and industrial applications. The various types of RF amplifiers include low noise amplifiers, power amplifier, pulse amplifier, bi-directional amplifier, multi-carrier amplifier, buffer amplifier, DLVA, SDLVA, ERDLVA, and limiting amplifiers.