Patent ID: 8923789

Claim:
A portable electronic device, comprising: a wireless receiver unit for receiving a wireless signal from a transmitting device, the wireless receiver unit including an antenna for receiving an electromagnetic signal and providing a received electric input signal, and a receiver for providing a recovered electric signal from the received electric input signal; and an impedance matching circuit for matching an electric impedance of the antenna to the receiver, wherein the receiver includes a gain stage, the gain stage including a variable gain stage in the form of an Automatic Gain Control unit for automatically determining an AGC-gain value for application to an AGC-input signal to provide an appropriate signal level of the recovered electric signal when the level of said AGC-input signal is in a range between a predetermined minimum signal level and a predetermined maximum signal level corresponding to maximum and minimum AGC-gain values, respectively, the gain stage is configured to amplify the received electric input signal, but not to attenuate the received electric input signal, the portable electronic device further includes a control unit receiving said AGC-gain value and providing an impedance matching control signal depending on said AGC-gain value to said impedance matching circuit, the control unit is configured to change the impedance matching of the antenna to the receiver by supplying the impedance matching control signal to the impedance matching circuit, and the control unit is further configured to decrease the impedance matching of the impedance matching circuit when said AGC-gain value is below a predefined minimum threshold AGC-gain value, thereby attenuating the received electric input signal when its level is larger than an upper limit of a dynamic range of the gain stage.