Transmitter circuit for mobile telephone set compatible with two different systems

Abstract

A transmitter circuit is configured of a first power amplifier of a variable gain type for amplifying first transmit signals, a second power amplifier of a fixed gain type for amplifying second transmit signals and a preamplifier into which the first or second transmit signals are entered, for supplying the first transmit signals to the first power amplifier and the second transmit signals to the second power amplifier, wherein the preamplifier is changed over so that its gain is fixed when the first transmit signals are to be amplified or is variable when the second transmit signals are to be amplified, and the gain of the first power amplifier and the gain of the preamplifier are controlled with a transmit power setting signal for setting amplitudes of transmit signals supplied by the first and second power amplifiers.

Dependencies are inferred from the claim text.