| 摘要 |
<p>PURPOSE: To obtain a portable telephone set which is reduced in power consumption and has small spurious radiation at the time of transmission and reception. CONSTITUTION: A variable AMP control circuit 105 varies the gains of variable attenuation circuits 101a and 101b according to received electric field intensity. Consequently, the gains of the variable attenuation circuits 101a and 101b are adjusted, so leaks in mixers (5) 35 and (1) 7 in following stages are reduced and the isolation between a PLLA circuit and a PLLB circuit is improved. Consequently, the spurious radiation is small at the time of transmission and reception. Further, a power source control circuit 106 controls power supply to PLLAMPs 102a and 102b according to transmission and reception timing, so neither the PLLAMP 102a nor 102b consumes electric power except in its transmission and reception timing.</p> |
