| 摘要 |
PURPOSE: A transmitting apparatus for radio frequency amplification in communication systems is provided to increase power efficiency and system capacity. CONSTITUTION: A transmitting control part(61) provides a transmitting output control signal, a gain control signal and a radio frequency switch control signal. A variable gain amplifier(62) amplifies the voltage of an intermediate frequency signal inputted through an input terminal, according to a transmitting control signal controlled through the transmitting control part(61). Integrators(63,67), composed of resistors(R63,R67) and capacitors(C63,C67), calculate the pulse width mean value of the transmitting output control signal and the gain control signal provided from the transmitting control part(61). A frequency conversion part(64) converts the intermediate frequency signal transferred from the variable gain amplifier(62) into a radio frequency signal. A linear driving amplifier(65) amplifies the radio frequency converted by the frequency conversion part(64). A power amplifier(66) amplifies the power of the radio frequency signal transferred from the linear driving amplifier(65), according to the gain control signal controlled through the transmitting control part(61). Switches(68,69) selectively transfer the radio frequency switch control signal controlled by the transmitting control part(61). |
