Harmonic reject receiver architecture and mixer
View Patent ↗Receiver architectures and methods of processing harmonic rich input signals employing harmonic suppression mixers are disclosed herein. The disclosed receivers, mixers, and methods enable a receiver to achieve the advantages of switching mixers while greatly reducing the mixer response to the undesired harmonics. A harmonic mixer can include a plurality of mixers coupled to an input signal. A plurality of phases of a local oscillator signal can be generated from a single local oscillator output. Each of the phases can be used to drive an input of one of the mixers. The mixer outputs can be combined to generate a frequency converted output that has harmonic rejection.
1. A receiver comprising:
a polyphase filter coupled to an input of said receiver and operable to generate a plurality of phases of an RF signal received via said input of said receiver;
a control signal generator operable to generate a control signal, wherein the control signal comprises a plurality of transitions during a period of a local oscillator signal, wherein each distinct transition in the plurality of transitions corresponds to a phase shift of the local oscillator signal;
a plurality of harmonic reject mixers, each of said harmonic reject mixers comprising a plurality of mixing circuits operable to receive one of the plurality of phases of the RF signal received via said input and the control signal, wherein each of the mixing circuits is operable to:
generate a product of the one of the plurality of phases of the RF signal received via said input and the control signal, wherein the product is generated according to a distinct transition in the plurality of transitions, and
apply a scaling factor to the one of the plurality of phases of the RF signal received via said input according to a sinusoidal function of a phase shift corresponding to the distinct transition in the plurality of transitions; and
an adder operable to combine the products generated by the plurality of mixing circuits to provide an output signal.
2. The receiver of claim 1 , wherein the scaling factor is applied to the product of the RF signal received via said input and the control signal.
3. The receiver of claim 1 , wherein the receiver comprises a demodulator operable to receive the output signal.
4. The receiver of claim 1 , wherein each of the plurality of mixing circuits comprises a switching mixer.
5. The receiver of claim 1 , wherein each of the plurality of mixing circuits comprises a CMOS switching mixer.
6. The receiver of claim 1 , wherein the output signal is a baseband signal.
7. The receiver of claim 1 , wherein the output signal is an intermediate frequency signal.
8. The receiver of claim 1 , wherein the RF signal received via said input is a common RF signal.
9. The receiver of claim 1 , wherein the plurality of mixing circuits consists of an odd number of mixers.
10. The receiver of claim 1 , wherein the RF signal received via said input signal comprises a television signal.
11. A receiver comprising:
a polyphase filter coupled to an input of said receiver and operable to generate a plurality of phases of an RF signal received via said input of said receiver;
an oscillator operable to generate an oscillator signal comprising a plurality of transitions during each time period in a plurality time periods, wherein each distinct transition in the plurality of transitions during one time period corresponds to a distinct phase shift;
a plurality of harmonic reject mixers, each of said harmonic reject mixers comprising a plurality of mixing circuits operable to receive one of the plurality of phases of the RF signal received via said input and the oscillator signal, wherein each of the mixing circuits is operable to:
apply a scaling factor to the RF signal received via said input according to a sinusoidal function of a distinct phase shift, and
generate a product of the RF signal received via said input and the oscillator signal according to a distinct transition during each time period in the plurality time periods, wherein the distinct transition is associated with the distinct phase shift; and
an adder operable to combine the products generated by the plurality of mixing circuits to provide an output signal.
12. The receiver of claim 11 , wherein the scaling factor is applied to the product of the RF signal received via said input and the oscillator signal.
13. The receiver of claim 11 , wherein the receiver comprises a demodulator operable to receive the output signal.
14. The receiver of claim 11 , wherein each of the plurality of mixing circuits comprises a switching mixer.
15. The receiver of claim 11 , wherein each of the plurality of mixing circuits comprises a CMOS switching mixer.
16. The receiver of claim 11 , wherein the output signal is a baseband signal.
17. The receiver of claim 11 , wherein the output signal is an intermediate frequency signal.
18. The receiver of claim 11 , wherein the RF signal received via said input is a common RF signal.
19. The receiver of claim 11 , wherein the plurality of mixing circuits consists of an odd number of mixers.
20. The receiver of claim 11 , wherein the RF signal received via said input comprises a television signal.