Patent ID: 6421546
Filing Date: 2002-07-16
Classification: H04B

Abstract:
A signal transmission circuit of a wireless telephone handset comprising:a voice transformation circuit for transforming a user's voice into a voice signal; a voice modulator electrically connected to the voice transformation circuit for modulating the voice signal and transforming it into a radio frequency signal; a power amplifier electrically connected to the voice modulator for amplifying the radio frequency signal; a first switch electrically connected to the power amplifier for turning the power amplifier on and off; a second switch electrically connected between the voice modulator and power amplifier for controlling the transmission of the radio frequency signal; an antenna for transmitting the radio frequency signal outputted from the power amplifier; and a control circuit for controlling operations of the telephone handset; wherein when the telephone handset is transmitting the radio frequency signal using the antenna, the control circuit turns on the first switch and the second switch so that the radio frequency signal generated by the voice modulator can be amplified by the power amplifier and then betransmitted through the antenna, and when the telephone handset is receiving a radio frequency signal, the control circuit turns off the first switch and the second switch to reduce power consumption and prevent the radio frequency signal generated by the voice modulator from being transmitted into the power amplifier.