Mobiltelefon.

摘要

A portable telephone including a synthesized local oscillator using a voltage controlled oscillator (14) in the receiver section (3) and receiving its operation power from either built-in battery (7) or an external power source. A first external voltage substantially equal to the output voltage of the built-in batteries and a second external voltage higher than the first voltage are received at respective terminals (8,9) and used as the external power source voltage. A power selector (23) supplies to the voltage controlled oscillator the power from the built-in battery when the telephone is powered by the built-in battery, or the power from the second external voltage, which is higher than the battery voltage, when the telephone is powered from the external power source.