Semiconductor integrated circuit for communication and portable communication terminal
First Claim
1. A semiconductor integrated circuit for communication, including a transmission circuit having a phase control loop for controlling phase of a carrier wave and an amplitude control loop for controlling amplitude of a transmission output signal, comprising a calibration circuit which compares a feedback signal with an output signal of a modulation circuit while changing electric parameters of any of circuits on the amplitude control loop step by step, detects variations in a loop gain, and corrects a loop band by changing the characteristics of any of the circuits on the amplification control loop in accordance with the detected variations.
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Accused Products
Abstract
The present invention provides a semiconductor integrated circuit for communication (radio frequency IC) capable of detecting and correcting variations in an amplitude loop band of a transmission circuit having a phase control loop and an amplitude control loop without using an external measuring apparatus. In a semiconductor integrated circuit for communication (radio frequency IC) including a transmission circuit having a phase control loop for controlling the phase of a carrier wave and an amplitude control loop for controlling the amplitude of a transmission output signal, a calibration circuit for detecting variations in a loop gain of the amplitude control loop and correcting the loop band is provided. The calibration circuit detects variations in a loop gain by comparing a feedback signal with an output signal of a modulation circuit while changing electric parameters of any of circuits on the amplitude control loop step by step, and corrects the loop band by changing characteristics of any of the circuits on the amplitude control loop in accordance with the detected variations.
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Citations
10 Claims
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1. A semiconductor integrated circuit for communication, including a transmission circuit having a phase control loop for controlling phase of a carrier wave and an amplitude control loop for controlling amplitude of a transmission output signal, comprising
a calibration circuit which compares a feedback signal with an output signal of a modulation circuit while changing electric parameters of any of circuits on the amplitude control loop step by step, detects variations in a loop gain, and corrects a loop band by changing the characteristics of any of the circuits on the amplification control loop in accordance with the detected variations.
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2. A semiconductor integrated circuit for communication, including a transmission circuit having a phase control loop for controlling phase of a carrier wave and an amplitude control loop for controlling amplitude of a transmission output signal, comprising
a gain variation detection circuit which detects variations in a loop gain by comparing a feedback signal with an output signal of a modulation circuit while changing electric parameters of any of circuits on the amplitude control loop step by step, and outputs a detection result.
Specification