HARMONIC REJECT RECEIVER ARCHITECTURE AND MIXER

• US 20120302193A1
• Filed: 08/07/2012
• Published: 11/29/2012
• Est. Priority Date: 12/10/2004
• Status: Active Grant

• Current Assignee: Maxlinear Incorporated
• Original Assignee: Maxlinear Incorporated
• Inventors: Seendripu, Kishore, Montemayor, Raymond, Ye, Sheng, Chang, Glenn, Ling, Curtis
• Granted Patent: US 8,374,569 B2
• Time in Patent Office: Days
• US Class Current: 455/314
• CPC Class Codes: H03D 2200/0086 Reduction or prevention of harmonic frequencies
• CPC Class Codes: H03D 3/007 by converting the oscillations into two quadrature related signals H03D3/245 takes precedence
• CPC Class Codes: H03D 3/008 Compensating DC offsets
• CPC Class Codes: H03D 3/009 Compensating quadrature phase or amplitude imbalances
• CPC Class Codes: H03D 7/14 Balanced arrangements
• CPC Class Codes: H03D 7/1441 using field-effect transistors H03D7/145 takes precedence
• CPC Class Codes: H03D 7/1458 Double balanced arrangements, i.e. where both input signals are differential
• CPC Class Codes: H03D 7/1475 Subharmonic mixer arrangements
• CPC Class Codes: H03D 7/165 at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature combined with amplitude demodulation H03D1/2245, combined with angle demodulation H03D3/007; N-path filters H03H19/002
• CPC Class Codes: H03D 7/166 using two or more quadrature frequency translation stages
• CPC Class Codes: H03H 11/22 providing two or more phase shifted output signals, e.g. n-phase output
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/109 by improving strong signal performance of the receiver when strong unwanted signals are present at the receiver input
• CPC Class Codes: H04B 1/12 Neutralising, balancing, or compensation arrangements
• CPC Class Codes: H04B 1/26 for superheterodyne receivers multiple frequency-changing H03D7/16
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04J 1/18 in which all the carriers are amplitude-modulated H04J1/02 takes precedence in telephony H04Q11/02, H04Q11/023; in stereophony H04H; in telegraphy H04L5/06; in telemetry G08C15/02, G08C15/04
• CPC Class Codes: H04L 27/34 Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems

Abstract

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.

Claims

1. A harmonic reject mixer comprising:

a plurality of mixers, each mixer having a common radio frequency (RF) input;

a phase shifter having an input coupled to a common local oscillator (LO) input and a plurality of phase shifted outputs, each of the outputs coupled to a LO input on a corresponding mixer; and

a combiner having a plurality of inputs, each input coupled to an output from an associated mixer, and configured to provide a combined intermediate frequency (IF) output.

2. The mixer of claim 1, wherein each of the plurality of mixers comprises a switching mixer.

4. The mixer of claim 1, wherein the phase shifter comprises a plurality of distinct phase shifters, each configured to provide a distinct predetermined phase shift.

5. The mixer of claim 1, wherein the phase shifter is configured to generate a plurality of phase shifted outputs equally spaced about the span of −

90 to +90 degrees.

6. The mixer of claim 1, wherein:

the plurality of mixers comprises three distinct mixers; and

the plurality of phase shifted outputs comprise outputs shifted by −

45, 0, and +45 degrees.

7. The mixer of claim 1, further comprising a plurality of amplifiers, each of the plurality of amplifiers coupled to a distinct one of the plurality of mixers and configured to amplify a mixer output by a gain based at least in part on an LO phase shift.

38. The harmonic mixer of claim 7, wherein the gain is proportional to a sinusoidal function of the phase associated with the LO phase shift.

39. The harmonic mixer of claim 1, wherein a difference between a frequency of the input and a frequency of the LO signal is greater than a channel bandwidth.

40. The harmonic mixer of claim 1, wherein the common LO input comprises a plurality of transitions over one LO period and each phase shifted output is generated according to a distinct transition in the plurality of transitions and each distinct transition in the plurality of transitions corresponds to the phase of each phase shifted output in the plurality of phase shifted outputs.

3. (canceled)

8. A method of harmonic rejection mixing, the method comprising:

generating a plurality of phases of a LO signal;

mixing an input signal with each of the plurality of phases of the LO signal to generate a plurality of mixed intermediate frequency (IF) output signals; and

combining the plurality of mixed IF output signals to provide an IF mixer output.

9. The method of claim 8, wherein mixing the input signal comprises:

coupling the input signal to a plurality of switching mixers; and

driving each of the plurality of switching mixers with a distinct one of the plurality of phase of the LO signal.

10. The method of claim 8, wherein generating the plurality of phases of the LO signal comprises phase shifting the LO signal using a plurality of distinct phase shifters, each of the plurality of distinct phase shifters providing a distinct phase shift.

11. The method of claim 8, wherein generating the plurality of phases of the LO signal comprises generating an odd number of distinct phases of the LO signal equally spaced about a span of −

90 to +90 degrees.

12. The method of claim 8, wherein combining the plurality of mixed IF output signals comprises summing the plurality of mixed IF output signals.

13. The method of claim 8, further comprising amplifying each of the plurality of mixed IF output signals by a gain based on an LO phase shift.

37. The method of claim 8, wherein a difference between a frequency of the input and a frequency of the LO signal is greater than a channel bandwidth.

41. The method of claim 13, wherein the gain is proportional to a sinusoidal function having a phase associated with the LO phase shift.

14-23. -23. (canceled)

24. A harmonic reject mixer comprising:

a plurality of mixing circuits operable to receive an input signal and a plurality of local oscillator (LO) signals having different phases, each of the mixing circuits operable to receive a different one of the plurality of local oscillator signals and being adapted to;

generate a product of the input signal and the received local oscillator signal; and

scale the product according to a sinusoidal function having a phase associated with the received local oscillator signal; and

an adder operable to combine a plurality of outputs from the plurality of mixing circuits.

25. The harmonic mixer of claim 24, wherein the combined plurality of outputs corresponds to a demodulator input.

26. The harmonic mixer of claim 24, wherein each LO signal in the plurality of LO signals is generated according to a control signal that comprises a plurality of transitions over one LO period and each distinct transition in the plurality of transitions corresponds to the phase of each LO signal in the plurality of LO signals.

27. The harmonic mixer of claim 24, wherein each of the plurality of mixing circuits comprises a switching mixer.

28. The harmonic mixer of claim 24, wherein the plurality of mixing circuits is an odd number of mixing circuits.

29. The harmonic mixer of claim 24, wherein the input comprises a specified channel and a difference between a frequency of the specified channel and a frequency of the LO signal is less than a bandwidth of the specified channel.

30. The harmonic mixer of claim 29, wherein the adder output is baseband.

31. The harmonic mixer of claim 29, wherein the adder output is substantially baseband.

32. The harmonic mixer of claim 31, wherein the difference between the frequency of the specified channel and the frequency of the LO signal is non-zero.

33. The harmonic mixer of claim 24, wherein the input is a common RF signal.

34. The harmonic mixer of claim 24, wherein the input comprises a specified channel and a difference between a frequency of the specified channel and a frequency of the LO signal is greater than a bandwidth of the specified channel.

35. The harmonic mixer of claim 34, wherein the adder output is an IF output.

36. The harmonic mixer of claim 26, wherein the number of distinct transitions in the plurality of transitions is equal to a number of mixing circuits in the plurality of mixing circuits.