Communication semiconductor integrated circuit, a wireless communication apparatus, and a loop gain calibration method

Abstract

A polar-loop wireless communication apparatus includes, on a forward path between an amplitude detector and a power amplifier which constitute an amplitude control loop, a variable gain amplifier and a switch to change characteristics of a loop filter to output a frequency bandwidth of the amplitude control loop to an order less than an order for normal operation. The system is operated with the characteristics set to the lower order to measure outputs from the power amplifier to calibrate the output power of the power transmitter, and the register is operated with the characteristics set to the higher order to measure the open loop gain of the amplitude control. According to results of the calculation, data to correct gain characteristics of the variable gain amplifier with respect to an output control signal is stored in a nonvolatile memory of a baseband circuit.

1 - 22 . (canceled)  
   
   
       23 . A wireless communication apparatus comprising: 
 a baseband circuit which generates first signals to be transmitted; and    a transmitter which includes a modulator which modulates the first signals and generates a modulated signal, a phase detector which detects the modulated signal and outputs a phase control signal, an amplitude detector which detects the modulated signal and outputs an amplitude control signal, an oscillator which receives the phase control signal and outputs a transmission signal, a power amplifier which receives the transmission signal and the amplitude signal and outputs an amplified transmission signal, a power detector which detects an output power of the amplified transmission signal, a first amplifier which couples the power detector and the amplitude detector, a second amplifier which couples the amplitude detector and the power amplifier, and a gain controller which instructs gain information to the first amplifier and the second amplifier in accordance with a power instruction signal from the baseband circuit and controls respective gain in mutually opposing directions,    wherein the transmitter has a register which stores correction data for correcting the variation of the output power characteristic of the power amplifier from the baseband circuit.    
   
   
       24 . The wireless communication apparatus according to  claim 23 , 
 wherein the correction data stored in the register includes:    corrective data to correct slope of gain characteristics of the second amplifier circuit with respect to the power instruction signal; and    corrective data to correct gain offset of gain characteristics of the second amplifier circuit with respect to the power instruction signal.    
   
   
       25 . The wireless communication apparatus according to  claim 23 , 
 wherein the transmitter further includes a switching means which receives the power instruction signal and an output signal of the second amplifier and supplies one of the power instruction signal and the output signal in accordance with an instruction from the baseband circuit, and    wherein the power amplifier is controlled by the output signal in a phase and amplitude modulation mode and is controlled by the power instruction signal in a phase modulation mode.    
   
   
       26 . The wireless communication apparatus according to  claim 23 , 
 wherein the register is a nonvolatile memory.    
   
   
       27 . The wireless communication apparatus according to  claim 23 , 
 wherein the gain controller generates a bias current as the gain information for the second amplifier circuit according to the correction data stored in the register.