An apparatus and method suppress unwanted signal components in receiving signals during wireless communication. A first circuitry is arranged to process a first signal, a second circuitry is arranged to apply transferred impedance filtering on a second signal according to a filter clock frequency, a signal branching circuitry is arranged to branch an input signal into the first circuitry and the second circuitry, and a signal combining circuitry is arranged to combine the processed first signal and the filtered second signal such that signal components of the first signal processed in the first circuitry and the filtered second signal are in-phase for signal frequencies equal to the filter clock frequency.
1. Apparatus for use in a communication device, the apparatus comprising:
a first circuitry arranged to process a first signal;
a second circuitry arranged to apply transferred impedance filtering on a second signal according to a filter clock frequency;
a signal branching circuitry arranged to branch an input signal into the first circuitry and the second circuitry; and
a signal combining circuitry arranged to combine the processed first signal and the filtered second signal such that signal components of the first signal processed in the first circuitry and the filtered second signal are in-phase for signal frequencies equal to the filter clock frequency.
2. The apparatus according to claim 1 , comprising at least one continuous time filter stage connected to either one of the signal branching circuitry and the signal combining circuitry,
wherein the filter clock frequency approximately matches a frequency passband edge of the at least one continuous time filter stage.
3. The apparatus according to claim 1 , wherein:
the first circuitry comprises a first scaling processor arranged to apply a first scaling factor, and
the second circuitry comprises a second scaling processor arranged to apply a second scaling factor.
4. The apparatus according to claim 1 , wherein the second circuitry is arranged to apply the transferred impedance filtering on the second signal according to the filter clock frequency by consecutively connecting a plurality of capacitors in a forward direction and consecutively connecting the plurality of capacitors in a reverse direction in accordance with the filter clock frequency.
5. The apparatus according to claim 1 , wherein the signal combining circuitry comprises:
a first voltage current converter circuitry in operable connection with the first circuitry branch and arranged to output a first current;
a second voltage current converter circuitry in operable connection with the second circuitry branch and arranged to output a second current; and
an adding circuitry arranged to add the first current to the second current to produce a sum current and to output the sum current.
6. The apparatus according to claim 5 , wherein the first voltage current converter circuitry and the second voltage current converter circuitry are arranged to realize application of scaling factors to the first current and the second current, respectively.
7. The apparatus according to claim 1 , wherein the first circuitry, the second circuitry, the signal branching circuitry, and the signal combining circuitry are arranged for use in a wireless communication system according to the Long Term Evolution and/or the Wideband Code Division Multiple Access specifications.
8. The apparatus according to claim 1 , the apparatus being arranged for use in a mobile phone and comprising:
user interface circuitry; and
user interface software arranged to enable user control through use of a human-machine-interface.
9. The apparatus according to claim 8 , wherein the human-machine-interface comprises a display.
10. The apparatus according to claim 1 , the apparatus being arranged for use in a wireless communication device and comprising:
wired interface circuitry; and
wireless transceiver circuitry.
11. A mobile phone comprising the apparatus according to claim 1 .
12. A method for use in a communication device, the method comprising:
branching an input signal into a first signal and a second signal;
processing the first signal in a first circuitry;
transferred impedance filtering the second signal in a second circuitry according to a filter clock frequency; and
combining the processed first signal and the filtered second signal such that signal components of the processed first signal and the filtered second signal are in-phase for signal frequencies equal to the filter clock frequency.
13. The method according to claim 12 , comprising continuous time filtering either the input signal prior to branching the input signal or an output signal corresponding to the combination of the processed first signal and filtered second signal,
wherein the filter clock frequency approximately matches a frequency passband edge of the continuous time filter.
14. The method according to claim 12 , comprising:
applying a first scaling factor to the processed first signal; and
applying a second scaling factor to the filtered second signal.
15. The method according to claim 12 , wherein the transferred impedance filtering of the second signal in the second circuitry according to a filter clock frequency comprises consecutively connecting a plurality of capacitors in a forward direction and consecutively connecting the plurality of capacitors in a reverse direction in accordance with the filter clock frequency.
16. The method according to claim 12 , wherein combining the processed first signal and the filtered second signal comprises:
voltage current conversion of the processed first signal and outputting a first current;
voltage current conversion of the filtered second signal and outputting a second current; and
adding the first current to the second current to produce a sum current and outputting the sum current.
17. The method according to claim 16 , wherein the voltage current conversion of the processed first signal and the filtered second signal comprises applying scaling factors to the first current and the second current respectively.