Patent ID: 6571087
Filing Date: 2003-05-27
Classification: H03G,H04B,H04W

Abstract:
A radio transmitter apparatus having:a transmission power generating stage for performing frequency conversion on, amplifying, and outputting an input signal; a detection unit partially branching the output of the transmission power generating stage and outputting a detection voltage; an ALC circuit for performing automatic level control (ALC) with respect to said transmission power generating stage according to the detection output from the detection unit; and an ATPC unit for performing automatic power control (ATPC) for operating said transmission power generating stage and said ALC circuit in either of a high power mode or a low power mode; the detection unit being configured by: a first detection unit which becomes effective in said low power mode and a second detection unit which becomes effective in said high power mode, wherein, said first detection unit comprises a first coupler for said branching with a first degree of coupling and a first detector, and said second detection unit comprises a second coupler for said branching with a second degree of coupling and a second detector, wherein the first degree of coupling is larger than the second degree of coupling, wherein said first detection unit is provided with a limiter circuit receiving as its input the output from said first coupler and applying the output to said first detector, and wherein â€ƒthe limiter circuit has characteristics in that the output is saturated when the input from the first coupler is at a high level, while also having characteristics in that the output thereof linearly varies along with the input when the input from the first coupler is at a low level.