Patent ID: 8233856

Claim:
A communications circuit for processing a signal in at least one predetermined communications standard having transition periods during which requirements for distortion and/or spurious emission are relaxed, the communications circuit comprising: an input stage for providing a signal in the at least one predetermined communications standard; an output stage for outputting a signal received from the input stage; a controlled impedance stage coupled between the input stage and the output stage and including a switched capacitor array for changing impedance of the controlled impedance stage; a driver for driving the switched capacitor array; and a driver control unit arranged to control the driver to switch selected capacitors of the switched capacitor array during the transition periods; wherein the driver is arranged to drive the switched capacitor array using a higher voltage or a lower voltage across selected capacitors, wherein the driver is arranged to switch the selected capacitors using the higher voltage, to hold the higher voltage for a predetermined time, and after the predetermined time to start adjusting the higher voltage across the selected capacitors towards the lower voltage.