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Adaptive radio transceiver with a local oscillator

Imported: 24 Feb '17 | Published: 11 Jun '02

Hooman Darabi, Ahmadreza Rofougaran, Maryam Rofougaran

USPTO - Utility Patents

Abstract

An oscillator circuit is disclosed which includes an oscillator to generate a first signal having a first frequency, a second oscillation source to generate a second signal having a second frequency, the second oscillator comprising a frequency divider coupled to the oscillator, and a mixer to mix to the first and second signals, wherein the oscillator, frequency divider and mixer are each quadrature. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Description

DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:

FIG. 1 is a block diagram of a transceiver in accordance with an exemplary embodiment of the present invention;

FIG. 2 is a block diagram of the transceiver blocks including a receiver, transmitter and local oscillator in accordance with an exemplary embodiment of the present invention;

FIG. 3 is a block diagram of a mixer in accordance with an exemplary embodiment of the present invention;

FIG. 4 is a block diagram of a local oscillator (LO) architecture in accordance with an exemplary embodiment of the present invention;

FIG. 5 is a block diagram of an LO architecture in accordance with another exemplary embodiment of the present invention;

FIG. 6 is a block diagram of a LO architecture in accordance with an alternative exemplary embodiment of the present invention;

FIG. 7 is a block diagram of a LO architecture in accordance with an yet another exemplary embodiment of the present invention;

FIG. 8 is a block diagram of a limiting buffer for the LO architecture of FIG. 33 in accordance with an exemplary embodiment of the present invention;

FIG. 9 is a block diagram of a wide tuning range voltage controlled oscillator (VCO) in accordance with an exemplary embodiment of the present invention;

FIG. 10 is an electrical diagram of the wide tuning range VCO of FIG. 34 in accordance with an exemplary embodiment of the present invention;

FIG. 11 is a graphical depiction showing a typical VCO tuning curve;

FIG. 12 is a graphical depiction of a segmented VCO tuning curve in accordance with an exemplary embodiment of the present invention;

FIG. 13 is a block diagram of a cross-coupled VCO in combination with a frequency divider in accordance with an exemplary embodiment of the present invention;

FIG. 14 is a block diagram of a VCO in combination with a divider and polyphase circuit in accordance with an exemplary embodiment of the present invention;

Claims

1. An oscillator circuit, comprising:

2. The oscillator circuit of claim 1 wherein the quadrature mixer comprises a plurality of Gilbert cells.

3. The oscillator circuit of claim 1 wherein the oscillator comprises an in-phase (I) output and a quadrature (Q) output, the frequency divider comprises an I input coupled to the I output of the oscillator, a Q input coupled to the Q output of the oscillator, an I output, and a Q output, and the mixer comprises first, second, third and fourth mixers each having first and second inputs and an output, the I output from the oscillator being coupled to the first inputs of the first and third mixers, the Q output from the oscillator being coupled to the first inputs of the second and fourth mixers, the I output from the frequency divider being coupled to the second inputs of the first and fourth mixers, and the Q output from the frequency divider being coupled to the second inputs of the second and third mixers, the outputs of the first and second mixers being coupled together, and the outputs of the third and fourth mixers being coupled together.

4. The oscillator circuit of claim 3 wherein the first, second, third and fourth mixers each comprises a Gilbert cell.

5. The oscillator circuit of claim 3 further comprising a subtractor to combine the first and second mixer outputs, and a summer to combine the third and fourth mixer outputs.

6. The oscillator circuit of claim 3 wherein the frequency divider comprises an internal divider with input and output buffers.

7. The oscillator circuit of claim 6 herein the input buffer comprises a first buffer comprising the I input to the frequency divider, a second buffer comprising the Q input to the frequency divider, and a third buffer to combine outputs of the first and second buffers and couple the combined outputs of the first and second buffers to the internal divider, the internal divider having I and Q outputs, and wherein the output buffer comprises a first buffer coupled to the I output of the internal divider, and a second buffer coupled to the Q output of the internal divider, the first buffer of the output buffer having an output comprising the I output of the frequency divider, and the second buffer of the output buffer having an output comprising the Q output of the frequency divider.

8. The oscillator circuit of claim 1 wherein the mixed first and second signals comprises a third frequency equal to a sum of the first and second frequencies.

9. The oscillator circuit of claim 1 wherein the oscillator comprises a voltage controlled oscillator.

10. The oscillator circuit of claim 9 further comprising a phase locked loop configured to control the first frequency of the first signal generated by the voltage controlled oscillator.

11. An oscillator circuit, comprising:

12. The oscillator circuit of claim 11 wherein the quadrature mixer means comprises a plurality of Gilbert cells.

13. The oscillator circuit of claim 11 wherein the mixed first and second signals comprises a third frequency equal to a sum of the first and second frequencies.

14. The oscillator circuit of claim 11 wherein the oscillation means comprises a voltage controlled oscillator.

15. The oscillator circuit of claim 14 further comprising a phase locked loop configured to control the first frequency of the first signal generated by the voltage controlled oscillator.

16. A transceiver, comprising:

17. The transceiver of claim 16 wherein the quadrature mixer comprises a plurality of Gilbert cells.

18. The transceiver of claim 16 wherein the oscillator comprises an inphase (I) output and a quadrature (Q) output, the frequency divider comprises an I input coupled to the I output of the oscillator, a Q input coupled to the Q output of the oscillator, an I output, and a Q output, and the mixer comprises first, second, third and fourth mixers each having first and second inputs and an output, the I output from the oscillator being coupled to the first inputs of the first and third mixers, the Q output from the oscillator being coupled to the first inputs of the second and fourth mixers, the I output from the frequency divider being coupled to the second inputs of the first and fourth mixers, and the Q output from the frequency divider being coupled to the second inputs of the second and third mixers, the outputs of the first and second mixers being coupled together, and the outputs of the third and fourth mixers being coupled together.

19. The transceiver of claim 18 wherein the first, second, third and fourth mixers each comprises a Gilbert cell.

20. The transceiver of claim 18 further comprising a subtractor to combine the first and second mixer outputs, and a summer to combine the third and fourth mixer outputs.

21. The transceiver of claim 18 wherein the frequency divider comprises an internal divider with input and output buffers.

22. The transceiver of claim 21 wherein the input buffer comprises a first buffer comprising the I input to the frequency divider, a second buffer comprising the Q input to the frequency divider, and a third buffer to combine outputs of the first and second buffers and couple the combined outputs of the first and second buffers to the internal divider, the internal divider having I and Q outputs, and wherein the output buffer comprises a first buffer coupled to the I output of the internal divider, and a second buffer coupled to the Q output of the internal divider, the first buffer of the output buffer having an output comprising the I output of the frequency divider, and the second buffer of the output buffer having an output comprising the Q output of the frequency divider.

23. The transceiver of claim 16 wherein the mixed first and second signals comprises a third frequency equal to a sum of the first and second frequencies.

24. The transceiver of claim 16 wherein the oscillator comprises a voltage controlled oscillator.

25. The transceiver of claim 24 further comprising a phase locked loop configured to control the first frequency of the first signal generated by the voltage controlled oscillator.