Passive harmonic-rejection mixer
An electronic device comprising a passive harmonic-rejection mixer. The passive harmonic rejection mixer has an input connected to several sub-mixer stages, and the sub-mixer stages are connected to a summing module for generating the output. Each sub-mixing stage comprises a gating module and a respective amplifier, the gating module adapted to selectively pass the input signal or the input signal with inverted polarity under the control of control signals.
1. An electronic device comprising;
a passive harmonic-rejection mixer with an input for receiving an input signal and an output for supplying a output signal, wherein
the mixer comprises multiple segments connected to the input;
each respective one of the segments has a respective segment output for supplying a respective contribution to the output signal;
the mixer comprises a summing module connected to the respective segment outputs for summing the respective contributions for generating the output signal;
each respective segment comprises a respective gating module and a respective amplifier;
each respective gating module has a gating input connected to the input for receiving the input signal and a control input to receive a control signal;
each respective amplifier has an amplifier input connected to a gating output of the respective gating module;
each respective amplifier has an amplifier output connected to the respective segment output; and
each respective gating module is operative to selectively pass the input signal, or pass the input signal with inverted polarity, to the gating responsive to the control signal.
2. The electronic device of claim 1 , wherein each respective gating module is further operative to selectively block the input signal from the gating output under the control of the control signal.
3. The electronic device of claim 2 , wherein each respective amplifier output is connected to the respective segment output via a respective weighting module, the respective weighting module operative to weight the contribution to the output signal.
4. The electronic device of claim 3 , wherein each respective weighting module is a respective pair of resistors, a respective transconductance amplifier, or a respective voltage amplifier circuit.
5. The electronic device of claim 1 , wherein the gating input of each respective gating module is connected to the input for receiving the input signal via a respective pair of resistors, or via a respective transconductance amplifier.
6. The electronic device of claim 1 wherein
at least one of the segments comprises a further gating module and a further amplifier, wherein
the further gating module has a gating input connected to the input for receiving the input signal; and
the further amplifier has an amplifier input connected to a gating output of the further gating module, and an amplifier output connected to the segment output.
7. The electronic device of claim 6 , wherein for each respective segment the respective amplifier and the respective gating module form a unit cell of the segment, and wherein for each specific one of the segments the further gating module and the further amplifier form a further unit cell of the segment, and wherein the unit cell circuit configurations are all identical to one another.
8. The electronic device of claim 7 , wherein different segments comprise different numbers of unit cells, the number of unit cells in a segment being determined according to the size of the contribution that the segment is to make to the output signal.
9. The electronic device of claim 7 , wherein each respective segment is controlled by respective control signals, and wherein the control signals for a segment are applied to all the gating modules of the segment in the same way.
10. The electronic device of claim 1 , further comprising a control module for supplying the control signals to the gating modules.
11. The electronic device of claim 10 , wherein the control module supplies respective control signals to respective segments, the respective control signals all having the same waveforms as one another and being shifted in phase with respect to one another.