Linearization of an amplification in an RF amplifier

Claim 3

A coupling arrangement for the linearization of the radio frequency amplification of a radio telephone, for example a mobile telephone, wherein the radio frequency amplifier (B) is coupled in front of the antenna, in that branch of the loop defined by two duplex filters (DQ3A, DQ3B), coupled opposite to each other, in which the signal to be transmitted is traveling, the radio frequency ampli­fier comprising a power amplifier (Q1, Q2, Q3), a switching circuit for bias voltages, an amplifier power gain control circuit, and a voltage regulation circuit, characterized in that coupled to the input and the output of the radio frequency amplifier (B) there are means (Sk1, Sk2) on the basis of the information from which the control circuit for the power gain of the radio frequency amplifier controls the power amplification of the radio frequency amplifier (B) in such a manner that the amplification is linear and constant.

Claim 4

A coupling arrangement for the linearization of the radio frequency amplification of a radio telephone, for example a mobile telephone, wherein the radio frequency amplifier (B) is coupled in front of the antenna, in that branch of the loop defined by two duplex filters (DQ3A, DQ3B), coupled opposite to each other, in which the signal to be transmitted is traveling, the radio frequency ampli­fier comprising a power amplifier (Q1, Q2, Q3), a switching circuit for bias voltages, an amplifier power gain control circuit, and a voltage regulation circuit, characterized in that coupled to the input and the output of the radio frequency amplifier (B) there are means (Sk1, Sk2) on the basis of the information from which the control circuit for the power gain of the radio frequency amplifier controls the power amplification of the radio frequency amplifier (B) in such a manner that the amplification is linear and constant.

Claim 5

A coupling arrangement according to Claim 2, charac­terized in that the means coupled to the input and the output of the radio frequency amplifier are directional couplers (Sk1, Sk2).

Claim 6

A coupling arrangement according to Claim 2, charac­terized in that the power of the radio frequency amplifier (B) is controlled so that the voltage received from each directional coupler (Sk1, Sk2) is equally high.

Claim 7

A coupling arrangement according to Claim 2, charac­terized in that the booster gain control circuit is coupled so that, if there is no transmission power coming to the first directional coupler (Sk1), the control circuit switches off the supply voltage of the power amplifiers (Q1, Q2) of the radio frequency amplifiers.

Claim 8

A coupling arrangement according to Claim 2, charac­terized in that the switching circuit for the bias voltages switches the bias voltages to the power amplifiers (Q1, Q2, Q3) only if there is transmission power coming to the first directional coupler (Sk1) and if the supply voltages of the power amplifiers (Q1, Q2) of the radio frequency amplifier (B) are on.