| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a wireless apparatus realizing low power consumption, a highly efficient output power, output power control, and elimination of a DC offset being the problem of a wireless apparatus adopting the direct conversion system. <P>SOLUTION: The band of a loop filter of a synthesizer is more narrowed during idle channel searching as compared with the case during a speech. The wireless apparatus observes a radio wave environment, discriminates a characteristic required for the wireless apparatus suited to the radio wave environment by itself, reduces the power consumption suited to the performance, observes a consumed current of a power amplifier PA and reduces the loss of the antenna by adjusting a matching circuit (LNA or MIX) of the antenna 101. Further, the wireless apparatus eliminates the DC offset from transmission power and a reflected wave at transmission. In the case of eliminating the DC offset by using an AC coupling capacitor, the wireless apparatus corrects deterioration in the frequency characteristic of the reception system including the capacitor by digital processing. A transmission power detector is integrated in an IC and a detected signal is power leaking to the power supply or ground of the IC. <P>COPYRIGHT: (C)2004,JPO</p> |
