| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a Polar loop transmission apparatus for decreasing frequency shift of a VCO (voltage-controlled oscillator) even when two digital and analog phase detectors are switched. <P>SOLUTION: After the VCO 260 is locked through a path including the DPD (digital phase detector) 221, the control is shifted to the APD (analog phase detector) 231. In this case, the DPD 221 is stepwise turned off and the APD 231 is stepwise turned on. Since the DPD 221 and the APD 231 are switched momentarily in a conventional configuration, the deviation in the frequency of the VCO 260 has been caused by a phase difference due to a delay difference or the like between the path including the DPD 221 and the path including the APD 231. In Figure 1, since the DPD 221 and the APD 231 are slowly switched, the phase difference is slowly shifted, the frequency shift of the VCO 260 can be decreased. <P>COPYRIGHT: (C)2004,JPO |
