High dynamic range time-varying integrated receiver for elimination of off-chip filters
A quadrature mixer with an LO input is provided. The quadrature mixer receives a signal having a frequency F LO and a signal input having a frequency F SIG , and has an output that comprises an output impedance that is high at frequencies of |F LO −F SIG | and |F LO +F SIG | and low at other. A mixer coupled to the output impedance interacts with the output impedance such that an impedance presented at the signal input is high for signals at F SIG if F SIG is a predetermined signal frequency, and low at other frequencies.
1. A receiver circuit comprising:
a quadrature passive mixer having an input and an output;
one or more output impedances coupled to the output of the quadrature passive mixer wherein an input impedance of the quadrature passive mixer provides a band-pass response;
a low noise amplifier (LNA) having an input and an output coupled to the quadrature passive mixer, the LNA configured to provide substantially linear transconductance over a predetermined input range; and
wherein the LNA and the quadrature passive mixer are configured so that a band-pass mixer input impedance response is presented to the output of the LNA so as to substantially reduce a LNA voltage gain for unwanted signals presented to the LNA input.
2. The receiver of claim 1 , wherein the LNA is a common source amplifier and includes source degeneration.
3. The receiver of claim 2 , wherein:
LO inputs of one or more switches of the quadrature passive mixer are driven by buffers through series-resonant LC structures;
the series-resonant LC structures are tuned to an LO frequency; and
a peak-to-peak swing at the switches is enhanced beyond a breakdown voltage of the buffer.
4. The receiver of claim 1 , wherein the LNA is a differential amplifier.
5. The receiver of claim 1 , wherein:
a frequency of operation corresponds to a channel in a wireless voice communications band;
the linear transconductance of the LNA input reduces degradation of an in-band signal in the presence of an out-of band signal; and
the band-pass response of the mixer attenuates the out-of band signal so as to prevent the out-of-band signal from degrading the in-band signal at the output of the LNA.
6. The receiver of claim 5 , wherein the receiver is selected from one or more of the group comprising a low intermediate frequency receiver and a direct conversion receiver.
7. The receiver of claim 5 , wherein:
the in-band signal corresponds to a channel in a GSM band;
the LNA input is sufficiently linear so as to not significantly degrade sensitivity-level wanted signals in the presence of out-of band signals;
the band-pass action of the mixer attenuates out-of-band signals to prevent out-of-band signals from degrading wanted signals at the output of the LNA.
8. The receiver of claim 1 , wherein the quadrature passive mixer further comprises:
a plurality of NFETs and PFETs; and
wherein the NFETs and PFETs are driven with substantially differential signals.
9. The receiver of claim 1 , wherein the quadrature passive mixer further comprises:
a plurality of FET switches; and
wherein two or more of the FET switches are biased to approximately a same voltage.
10. The receiver of claim 1 , wherein the quadrature passive mixer further comprises:
a plurality of FET switches; and
wherein two or more of the FET switches are biased to approximately the same voltage.
11. A receiver circuit comprising:
a mixer having an input and an output;
one or more output impedances coupled to the output of the mixer wherein an input impedance of the mixer provides a band-pass response; and
a low noise amplifier (LNA) having an input and an output coupled to the mixer, the LNA configured to provide substantially linear transconductance over a predetermined input range.
12. The receiver of claim 11 , wherein the linear transconductance of the LNA input reduces degradation of an in-band signal in the presence of an out-of band signal.
13. The receiver of claim 11 , wherein the mixer further comprises:
a plurality of NFETs and PFETs; and
wherein the NFETs and PFETs are driven with substantially differential signals.
14. A receiver circuit comprising:
a quadrature passive mixer having an input and an output;
means coupled to the output of the quadrature passive mixer for providing a band-pass response of an input impedance of the quadrature passive mixer; and
a low noise amplifier (LNA) having an input and an output coupled to the quadrature passive mixer, the LNA configured to provide substantially linear transconductance over a predetermined input range.
15. The receiver of claim 14 , wherein the LNA and the quadrature passive mixer arc configured so that a band-pass mixer input impedance response is presented to the output of the LNAso as to substantially reduce a LNA voltage gain for unwanted signals presented to the LNA input.
16. The receiver of claim 14 , wherein:
a frequency of operation corresponds to a channel in a wireless voice communications band;
the linear transconductance of the LNA input reduces degradation of an in-band signal in the presence of an out-of band signal.
17. A receiver circuit comprising:
a mixer having an input and an output;
one or more output impedances coupled to the output of the mixer providing an input impedance of the mixer with a band-pass response;
a low noise amplifier (LNA) having an input and an output and providing substantially linear transconductance over a predetermined input range coupled to the mixer; and
wherein a band-pass mixer input impedance response is presented to the output of the LNA.
18. The receiver of claim 17 , wherein the quadrature passive mixer further comprises:
a plurality of NFETs and PFETs; and
wherein the NFETs and PFETs are driven with substantially differential signals.
19. The receiver of claim 17 , wherein the quadrature passive mixer further comprises:
a plurality of FET switches; and
wherein two or more of the FET switches are biased to approximately the same voltage.
20. A receiver comprising:
a quadrature passive mixer having an input and an output and an input impedance and providing a band-pass response;
a low noise amplifier (LNA) having an input and an output coupled to the quadrature passive mixer, the LNA configured to provide substantially linear transconductance over a predetermined input range; and
wherein the LNA and the quadrature passive mixer are configured so that a band-pass mixer input impedance response is presented to the output of the LNA so as to substantially reduce a LNA voltage gain for unwanted signals presented to the LNA input.
21. The receiver of claim 20 , wherein:
a frequency of operation corresponds to a channel in a wireless voice communications band;
the linear transconductance of the LNA input reduces degradation of an in-band signal in the presence of an out-of band signal; and
the band-pass response of the mixer attenuates the out-of band signal so as to prevent the out-of-band signal from degrading the in-band signal at the output of the LNA.