Mixer, mixer system and method

1. A mixer configured to sample a received input signal at a predefined oscillator frequency to generate a sampled input signal, and switch a polarity of the sampled input signal at a predefined polarity switching frequency to generate a polarity switched sampled input signal, wherein the polarity of the polarity switched sampled input signal is maintained as compared to the received input signal in a first polarity state and is reversed as compared to the received input signal in a second polarity state, wherein the first polarity state and the second polarity state switch between each other according to the predefined polarity switching frequency, wherein the oscillator frequency is selected to be a multiple or an integer multiple of the polarity switching frequency; and

wherein the mixer is configured to switch the polarity of the sampled input signal at points in time when the input signal is received at an input of the mixer and an output of the mixer at which the sampled input signal is provided is decoupled from each other.

2. The mixer as claimed in claim 1 , wherein the predefined oscillator frequency is different from the predefined polarity switching frequency.

3. The mixer as claimed in claim 1 , configured to couple, during sampling, an input of the mixer at which the input signal is received to an output of the mixer at which the sampled input signal is provided in a first state, and to decouple the input of the mixer from the output of the mixer in a second state.

4. The mixer as claimed in claim 3 , configured to switch between the first state and the second state at the oscillator frequency.

5. A mixer configured to sample a received input signal at a predefined oscillator frequency to generate a sampled input signal, and switch a polarity of the sampled input signal at a predefined polarity switching frequency to generate a polarity switched sampled input signal, configured to simultaneously receive a first data signal comprising a first frequency range and a second data signal comprising a second frequency range;

the first data signal and the second data signal being comprised by the input signal received; and

wherein the oscillator frequency and the polarity switching frequency are selected such that the first frequency range lies within a predefined frequency range around a positive difference between the oscillator frequency and the polarity switching frequency, and that the second frequency range lies within a predefined frequency range around a sum of the oscillator frequency and the polarity switching frequency.

6. The mixer as claimed in claim 5 , wherein a bandwidth of the predefined frequency range around the sum of the oscillator frequency and the polarity switching frequency, and a bandwidth of the predefined frequency range around the positive difference between the oscillator frequency and the polarity switching frequency equal a pass bandwidth of a filter of the mixer for filtering the sampled input signal.

7. The mixer as claimed in claim 6 , wherein a center frequency of the first frequency range is smaller than a center frequency of the second frequency range;

wherein the first frequency range and the second frequency range are disjoint; and

wherein the pass bandwidth of the filter is smaller than an amount of a difference between a lower limit of the first frequency range and an upper limit of the second frequency range.

8. A mixer configured to sample a received input signal at a predefined oscillator frequency to generate a sampled input signal, and switch a polarity of the sampled input signal at a predefined polarity switching frequency to generate a polarity switched sampled input signal, the mixer comprising a mixer stage configured to receive the input signal and provide the sampled input signal; and

further comprising an oscillator circuit configured to provide to the mixer stage an oscillator signal comprising the oscillator frequency and a polarity switching signal comprising the polarity switching frequency;

wherein the mixer stage is configured to provide the polarity switched sampled input signal based on the oscillator signal and the polarity switching signal,

wherein the oscillator circuit is configured to keep constant a phase relationship between the oscillator signal and the polarity switching signal, and

wherein the oscillator circuit is configured to provide the oscillator signal and the polarity switching signal such that a state change of the polarity switching signal will occur only at points in time when the oscillator signal is in a predefined state.

9. The mixer as claimed in claim 8 , wherein the mixer stage is configured such that in a predefined state of the oscillator signal, an input of the mixer stage at which the input signal is received is decoupled from an output of the mixer stage at which the sampled input signal is provided.

10. The mixer as claimed in claim 8 , wherein the oscillator circuit comprises a numerically controlled oscillator so as to provide the polarity switching signal such that the oscillator frequency is a multiple or an integer multiple of the polarity switching frequency.

11. A mixer configured to sample a received input signal at a predefined oscillator frequency to generate a sampled input signal, and switch a polarity of the sampled input signal at a predefined polarity switching frequency to generate a polarity switched sampled input signal, the mixer comprising a capacitance network for holding the polarity switched sampled input signal,

configured to simultaneously receive a first data signal comprising a first frequency range and a first center frequency, and a second data signal comprising a second frequency range and a second center frequency;

the first data signal and the second data signal being comprised by the input signal;

the second center frequency being higher than the first center frequency; and

a capacitance of the capacitance network being selected such that a pass bandwidth of a filter resulting from the capacitance is smaller, for the sampled input signal, than an amount of a difference between a lower limit of the first frequency range and an upper limit of the second frequency range.

12. A mixer configured to sample a received input signal at a predefined oscillator frequency to generate a sampled input signal, and switch a polarity of the sampled input signal at a predefined polarity switching frequency to generate a polarity switched sampled input signal, the mixer comprising a capacitance network for holding the polarity switched sampled input signal; and

further comprising a mixer stage configured to receive the input signal and provide the polarity switched sampled input signal to the capacitance network; and

wherein the capacitance network comprises a first capacitance permanently coupled to the mixer stage, and a second capacitance switchably coupled to the mixer stage.

13. The mixer as claimed in claim 12 , wherein the capacitance network further comprises a third capacitance switchably coupled to the mixer stage; and

wherein the second capacitance and the third capacitance are switched to be complementary to each other such that in a first phase wherein the second capacitance is coupled to the mixer stage, the third capacitance is decoupled from the mixer stage, and such that in a second phase wherein the second capacitance is decoupled from the mixer stage, the third capacitance is coupled to the mixer stage.

14. The mixer as claimed in claim 12 , configured such that switching of the second capacitance from a first phase wherein the second capacitance is coupled to the mixer stage to a second phase wherein the second capacitance is decoupled from the mixer stage will occur only at such points in time when an output of the mixer stage at which the sampled input signal is provided is decoupled from an input of the mixer stage at which the input signal is received.

15. A mixer system comprising:

a plurality of mixers, each of the mixers being configured to sample a received input signal at a predefined oscillator frequency to generate a sampled input signal and switch a polarity of the sampled input signal at a predefined polarity switching frequency to generate a polarity switched sampled input signal;

a clock provider for providing to each mixer among the plurality of mixers an oscillator signal comprising the predefined oscillator frequency and a polarity switching signal comprising the predefined polarity switching frequency;

wherein oscillator signals for different mixers are shifted in phase in relation to one another; and

wherein polarity switching signals for different mixers are shifted in phase in relation to one another.

16. The mixer system as claimed in claim 15 , wherein the oscillator frequency is different from the polarity switching frequency.

17. The mixer system as claimed in claim 15 , wherein the clock provider is configured to provide each of the mixers with its oscillator signal and its polarity switching signal such that a state change of a polarity switching signal of a mixer will occur only when the oscillator signal of the mixer comprises a predefined state wherein an output of the mixer at which the mixer provides its sampled input signal is decoupled from an input of the mixer at which the mixer receives the input signal.

18. The mixer system as claimed in claim 15 , wherein each of the mixers receives the same input signal.

19. A method comprising:

sampling a received input signal at a predefined oscillator frequency to generate a sampled input signal; and

switching a polarity of the sampled input signal at a predefined polarity switching frequency to generate a polarity switched sampled input signal;

wherein a first data signal comprising a first frequency range and a second data signal comprising a second frequency range are comprised by the receive signal; and

wherein the oscillator frequency and the polarity switching frequency are selected such that the first frequency range lies within a predefined frequency range around a positive difference between the oscillator frequency and the polarity switching frequency, and such that the second frequency range lies within a predefined frequency range around a sum of the oscillator frequency and the polarity switching frequency.

20. The method as claimed in claim 19 , wherein a center frequency of the first frequency range is smaller than a center frequency of the second frequency range, and the first frequency range and the second frequency range are disjoint;

wherein a bandwidth of the predefined frequency range around the sum of the oscillator frequency and the polarity switching frequency and a bandwidth of the predefined frequency range around the positive difference between the oscillator frequency and the polarity switching frequency are equal to a pass bandwidth of a filter for the sampled input signal; and

wherein the pass bandwidth of the filter is smaller than an amount of a difference between a lower limit of the first frequency range and an upper limit of the second frequency range.

21. A mixer comprising:

a sampling stage configured to sample a received input signal at a predefined oscillator frequency of an applied oscillator signal, and to maintain, during sampling, a polarity of the sampled input signal with regard to the received input signal when the oscillator signal is present at a first oscillator signal input of the sampling stage, and to switch, during sampling, a polarity of the sampled input signal with regard to the received input signal when the oscillator signal is present at a second oscillator signal input of the sampling stage; and

a switching signal provider configured to alternately apply the oscillator signal comprising a predefined polarity switching frequency at the first oscillator signal input of the sampling stage and at the second oscillator signal input of the sampling stage.