Time alignment of polar transmitter

• US 7,894,545 B1
• Filed: 08/13/2007
• Issued: 02/22/2011
• Est. Priority Date: 08/14/2006
• Status: Active Grant

• Current Assignee: NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Quintic Holdings (NXP Semiconductors NV)
• Inventors: Groe, John B.
• Primary Examiner(s): KIM, KEVIN
• Application Number:
  US11/837,983
• Time in Patent Office: 1,289 Days
• Field of Search: 375/295, 375/296, 375/300, 375/302, 455/73, 455/91, 455/108
• US Class Current: 375/295
• CPC Class Codes: H04L 27/361 Modulation using a single or unspecified number of carriers, e.g. with separate stages of phase and amplitude modulation

Abstract

An alignment apparatus for use with a polar transmitter system is disclosed herein. The alignment apparatus includes a signal alignment module configured to apply an amplitude modulation control signal and a frequency modulation control signal to the polar transmitter in accordance with a defined timing relationship. A time alignment network, operatively coupled between an output of the polar transmitter system and the signal alignment module, sets the defined timing relationship.

Claims

1. A polar transmitter system, comprising:

a direct synthesis modulator operative to generate an output signal based upon a reference signal, the direct synthesis modulator being responsive to an amplitude modulation control signal and a frequency modulation control signal; and

a signal alignment module configured to apply the amplitude modulation control signal and the frequency modulation control signal to the direct synthesis modulator in accordance with a defined timing relationship;

wherein the amplitude modulation control signal and the frequency modulation control signal are based upon an input amplitude modulation signal and an input phase or frequency modulation signal, respectively; and

wherein the signal alignment module includes a first latch arrangement which latches the input amplitude modulation signal and a second latch arrangement which latches the input phase or frequency modulation signal.

2. The polar transmitter system of claim 1 wherein the signal alignment module further includes a triggering network configured to establish the defined timing relationship between the amplitude modulation control signal and the frequency modulation control signal.

3. The polar transmitter system of claim 1 wherein the direct synthesis modulator includes a first control port and a second control port, the signal alignment module including a digital to analog converter for providing an analog version of the frequency modulation control signal to the first control port and a digital version of the frequency modulation control signal to the second control port.

4. The polar transmitter system of claim 3 wherein the direct synthesis modulator includes a voltage-controlled oscillator to which is applied the analog version of the frequency modulation control signal and a delta-sigma modulator to which is applied the digital version of the frequency modulation control signal.

5. The polar transmitter system of claim 4 wherein the direct synthesis modulator includes a phase-locked loop operatively connected to the delta-sigma modulator.

6. The polar transmitter system of claim 3 wherein the direct synthesis transmitter further includes an amplifier to which is applied the amplitude modulation control signal.

7. The polar transmitter system of claim 2 wherein the triggering network comprises a delay-locked loop connected between the first latch arrangement and the second latch arrangement.

8. A signal alignment module for use with a polar transmitter, the alignment module comprising:

a first latch arrangement which latches an input amplitude modulation signal;

a second latch arrangement which latches an input phase or frequency modulation signal; and

a triggering network for providing a first timing signal to the first latch arrangement and a second timing signal to the second latch arrangement wherein the triggering network establishes a defined time offset between the first timing signal and the second timing signal.

9. The alignment module of claim 8 wherein the triggering network includes a delay-locked loop.

10. An alignment apparatus for use with a polar transmitter system, the apparatus comprising:

a signal alignment module configured to apply an amplitude modulation control signal and a frequency modulation control signal to the polar transmitter in accordance with a defined timing relationship; and

a time alignment network, operatively coupled between an output of the polar transmitter system and the signal alignment module, for setting the defined timing relationship;

wherein the time alignment network includes;

a signal source for applying test signals to inputs of the signal alignment module, and

a control network for determining the defined timing relationship based upon output signals generated by the polar transmitter based upon the test signals.

11. The time alignment apparatus of claim 10 wherein the test signals of an I/Q format including in-phase and quadrature-phase components, the signal source converting the I/Q format of test signals to a polar format.

12. The time alignment apparatus of claim 11 wherein the signal source further includes:

a first interpolator for interpolating the in-phase components of the test signals;

a first filter operatively connected to an output of the first interpolator;

a second interpolator for interpolating the quadrature-phase components of the test signals, and

a second filter operatively connected to an output of the second interpolator.

13. An apparatus for adjusting signal time alignment within a polar transmitter system, the apparatus comprising:

a signal alignment module operative to apply control signals to the polar transmitter system; and

a time alignment network for setting a timing relationship imposed upon the control signals by the signal alignment module, the time alignment network including;

a signal source unit coupled to the signal alignment module,

a receiver coupled to an output of the polar transmitter system, and

a control network coupled between an output of the receiver and the signal alignment module.

14. The apparatus of claim 13 wherein the signal source produces test signals based upon a complex signal characterized by the in-phase (I) and quadrature-phase (Q) sequences:

I=[r₁,0,0,−

r₂,−

r₁,0,0,r₂] and Q=[0,r₂,r₁,0,0,−

r₂,−

r₁,0]

where r₁>

r₂.

15. The apparatus of claim 13 wherein the signal source produces test signals based upon a complex signal characterized by the in-phase (I) and quadrature-phase (Q) sequences:

I=[r₁,0,−

r₁,0] and Q=[0,r₂,0,−

r₂]

where r₁>

r₂.

16. The apparatus of claim 13 wherein the signal source produces test signals based upon a complex signal characterized by the in-phase (I) and quadrature-phase (Q) sequences:

I=[r₁,−

r₃,−

r₂,−

r₃,−

r₂,r₃] and Q=[0,r₅,r₄,−

r₅,−

r₄,0]

where r₁>

r₂ and r₄>

r₅.

17. The apparatus of claim 13 wherein the signal source produces test signals based upon a complex signal characterized by the in-phase (I) and quadrature-phase (Q) sequences:

I=[r₁,r₂,0,−

r₂,−

r₁,−

r₂,0,r₂] and Q=[0,r₂,r₁,r₂,0,−

r₂,−

r₁,−

r₂,]

where r₁>

r₂.

18. The apparatus of claim 13 wherein the signal source produces test signals based upon a complex signal characterized by the in-phase (I) and quadrature-phase (Q) sequences:

I=[r₁,r₃,r₂,r₄,0,−

r₄,−

r₂,−

r₃,−

r₁,−

r₃,−

r₂,−

r₄,0,r₄,r₂,r₃] and Q=[0,r₄,r₂,r₃,r₁,r₃,r₂,r₄,0,−

r₄,−

r₂,−

r₃,−

r₁,−

r₃,−

r₂,−

r₄]

where r₁>

r₂>

r₃>

r₄.

19. The apparatus of claim 13 wherein the signal source produces test signals based upon a complex signal that changes amplitude moving from odd symbols to even symbols and changes phase moving from even symbols to odd symbols.

20. The apparatus of claim 13 wherein the signal source produces test signals based upon a complex signal that includes a plurality of symbols, the complex signal changing in amplitude beginning with a first of the plurality of symbols and changing in phase every other symbol beginning with a second of the plurality of symbols different from the first of the plurality of symbols.

21. The apparatus of claim 13 wherein the receiver is disposed to detect a level of a predefined frequency component or tone.

22. The apparatus of claim 21 wherein the control network determines the timing relationship based on the detected level.