| 摘要 |
An external speaker is provided to enhance convenience of a user by enabling a user to select one of an external speaker function and an audio wireless transmission function. An amplifier amplifies an audio signal from a portable terminal to a predetermined level and outputs the amplified result through a speaker. A transmitter modulates the audio signal into an RF(Radio Frequency) signal and wirelessly transmits the modulated signal to a remote speaker system. A switch(304) selectively outputs the audio signal to one of a speaker output unit and the wireless transmitter. An intenna unit(312) receives a wireless radio signal and provides the received signal to a radio receiving block of the portable terminal through a connection plug. A charging circuit(316) charges an embedded battery by using a voltage from an external USB(Universal Serial Bus) cable. A battery(318) supplies power to the speaker unit and the wireless transmitter. A display unit(320) displays a charging state of the battery during a charging process. |
