Patent ID: 9588158
Date: 2017-03-07
CPC Classifications: G01R,H03F,H04B,H04W

Claim:
1. An apparatus for determining information on a power variation of a transmit signal, the apparatus comprising: a power amplifier module configured to amplify a radio frequency transmit signal to generate an amplified radio frequency transmit signal; an antenna module configured to transmit at least partly the amplified radio frequency transmit signal; a power variation determining module configured to determine a weighted sum of a first feedback signal and a second feedback signal derived from the amplified radio frequency transmit signal, wherein the first feedback signal and the second feedback signal comprise different dependencies on a varying impedance at the antenna module, wherein the power variation determining module is further configured to generate a power variation signal based on the weighted sum, wherein the power variation signal comprises information related to a power variation of the amplified radio frequency transmit signal; a coupled port configured to provide a forward coupled signal caused by the amplified radio frequency transmit signal; a feedback receiver module configured to generate the first feedback signal at least by a down conversion of the forward coupled signal from a radio frequency domain to a baseband domain of the apparatus; and a directional coupler comprising an input port, a transmitted port, and an isolated port, wherein the input port is configured to receive the amplified radio frequency transmit signal, wherein the transmitted port is configured to provide at least partly the amplified radio frequency transmit signal to the antenna module, wherein the isolated port is configured to provide a reverse coupled signal mainly caused by a reverse wave signal reflected due to a varying impedance mismatch at the antenna module received by the transmitted port, wherein the first feedback signal is based on the forward coupled signal and the second feedback signal is based on the reverse coupled signal; wherein the feedback receiver module is further configured to generate the second feedback signal at least by a down conversion of the reverse coupled signal from the radio frequency domain to the baseband domain of the apparatus.