Apparatuses and methods for generating a radio frequency signal, a modulator, a controller for a modulator, and a method for controlling a modulator

1. A controller for a modulator, comprising:

a control unit configured to control the modulator to generate a radio frequency signal based on an input signal using polar modulation, if the input signal has a first characteristic, and to control the modulator to generate the radio frequency signal using quadrature modulation, if the input signal has a different second characteristic,

wherein the first signal characteristic indicates that a sample of the input signal is located in a first region of a constellation diagram, and wherein the second characteristic indicates that the sample is located in a different second region of the constellation diagram; and

an output unit configured to supply a control signal for the modulator, the control signal indicating the modulation method determined by the control unit based on the input signal.

2. An apparatus for generating a radio frequency signal, comprising:

a modulator configured to generate the radio frequency signal based on an input signal; and

a controller configured to control the modulator to generate the radio frequency signal using polar modulation, if the input signal has a first characteristic,

wherein the first characteristic indicates that a sample of the input signal is located in a first region of a constellation diagram; and

wherein the controller is configured to control the modulator to generate the radio frequency signal using quadrature modulation, if the input signal has a different second characteristic indicating that the sample is located in a different second region of the constellation diagram.

3. The apparatus of claim 2 , wherein the constellation diagram is spanned by a first axis representing an in-phase component and an orthogonal second axis representing a quadrature component.

4. The apparatus of claim 3 , wherein the first region comprises the first axis and the second axis of the constellation diagram.

5. The apparatus of claim 4 , wherein, in the second region, a maximum distance of the sample to the origin of the constellation diagram is smaller than a first threshold value.

6. The apparatus of claim 5 , wherein, apart from the first axis and the second axis, a minimum distance of the sample to the origin of the constellation diagram is greater than the first threshold value in the first region.

7. The apparatus of claim 2 , wherein the second region corresponds to instantaneous frequencies of the radio frequency signal having a frequency deviation from a desired carrier frequency of the radio frequency signal that is greater than a second threshold value.

8. The apparatus of claim 7 , wherein the first region corresponds to instantaneous frequencies of the radio frequency signal having a frequency deviation from the desired carrier frequency of the radio frequency signal that is smaller than the second threshold value.

9. A method for controlling a modulator, comprising:

controlling the modulator to generate the radio frequency signal based on an input signal using polar modulation, if the input signal has a first characteristic,

wherein the first signal characteristic indicates that a sample of the input signal is located in a first region of a constellation diagram; and

controlling the modulator to generate the radio frequency signal using quadrature modulation, if the input signal has a different second characteristic indicating that the sample is located in a different second region of the constellation diagram.

10. The method of claim 9 , wherein the method further comprises supplying a control signal for the modulator, the control signal indicating the desired modulation method.

11. A method for generating a radio frequency signal, comprising:

generating the radio frequency signal based on an input signal using a modulator;

controlling the modulator to generate the radio frequency signal using polar modulation, if the input signal has a first characteristic,

wherein the first characteristic indicates that a sample of the input signal is located in a first region of a constellation diagram; and

controlling the modulator to generate the radio frequency signal using quadrature modulation, if the input signal has a different second characteristic indicating that the sample is located in a different second region of the constellation diagram.

12. The method of claim 11 , wherein the constellation diagram is spanned by a first axis representing an in-phase component and an orthogonal second axis representing a quadrature component.

13. The method of claim 12 , wherein the first region comprises the first axis and the second axis of the constellation diagram.

14. The method of claim 13 , wherein, in the second region, a maximum distance of the sample to the origin of the constellation diagram is smaller than a first threshold value.

15. The method of claim 14 , wherein, apart from the first axis and the second axis, a minimum distance of the sample to the origin of the constellation diagram is greater than the first threshold value in the first region.

16. The method of claim 11 , wherein the second region corresponds to instantaneous frequencies of the radio frequency signal having a frequency deviation from a desired carrier frequency of the radio frequency signal that is greater than a second threshold value.

17. The method of claim 16 , wherein the first region corresponds to instantaneous frequencies of the radio frequency signal having a frequency deviation from the desired carrier frequency of the radio frequency signal that is smaller than the second threshold value.