Hybrid I-Q polar transmitter with quadrature local oscillator (LO) phase correction

1. A hybrid polar in-phase quadrature (I-Q) transmitter, comprising:

an I-Q quantization circuit configured to,

receive an in-phase signal and a quadrature signal forming a first I-Q data pair, and

generate a quantized in-phase signal and a quantized quadrature signal forming a second I-Q data pair, respectively, based on a resolution information of a digital-to-analog converter (DAC) in a signal path of the quantized in-phase and quadrature signals, wherein the first and second I-Q data pairs form an I-Q constellation point; and

a quantization reduction circuit to minimize a quantization error associated with the DAC, coupled to the I-Q quantization circuit and configured to,

determine a first rotation angle and a second rotation angle based on the first I-Q data pair and the second I-Q data pair; and

generate a radio frequency (RF) output signal based on the first rotation angle and the second rotation angle.

2. The I-Q transmitter of claim 1 , wherein the quantization reduction circuit further

comprises a phase correction circuit coupled to the quantization circuit and configured to,

receive the in-phase signal, the quadrature signal, the quantized in-phase signal and the quantized quadrature signal; and

determine the first rotation angle and the second rotation angle based on the in-phase signal, the quadrature signal, the quantized in-phase signal and the quantized quadrature signal.

3. The I-Q transmitter of claim 2 , wherein the first rotation angle and the second rotation angle are determined based on a first predetermined relation and a second predetermined relation, respectively, based on the in-phase signal, the quadrature signal, the quantized in-phase signal and the quantized quadrature signal.

4. The I-Q transmitter of claim 3 , further comprising a memory circuit configured to store instructions to implement the first predetermined relation and the second predetermined relation.

5. The I-Q transmitter of claim 2 , wherein the quantization reduction circuit further

comprises a synthesizer circuit configured to,

receive the first rotation angle and the second rotation angle from the phase correction circuit;

generate a first phase corrected local oscillator (LO) signal with an added first correction phase, wherein the first correction phase corresponds to the first rotation angle; and

generate a second phase corrected local oscillator (LO) signal with an added second correction phase, wherein the second correction phase corresponds to the second rotation angle.

6. The I-Q transmitter of claim 5 , wherein the synthesizer circuit further comprises a first digital-to-time converter (DTC) to generate the first phase corrected LO signal and a second DTC to generate the second phase corrected LO signal.

7. The I-Q transmitter of claim 5 , wherein the quantization reduction circuit further comprises a first signal path and a second signal path configured to receive the quantized in-phase signal and the quantized quadrature signal, respectively, from the I-Q quantization circuit.

8. The I-Q transmitter of claim 7 , wherein the quantization reduction circuit further comprises a modulation circuit configured to apply a first rotation corresponding to the first rotation angle to the quantized in-phase signal and apply a second rotation corresponding to the second rotation angle to the quantized quadrature signal.

9. The I-Q transmitter of claim 8 , wherein the modulation circuit further comprises, the DAC, the resolution information of which is used in the I-Q quantization circuit to generate the quantized in-phase signal and the quantized quadrature signal,

wherein the DAC comprises a first DAC component located downstream of the first signal path and configured to receive and process the quantized in-phase signal, and a second DAC component located downstream of the second signal path and configured to receive and process the quantized quadrature signal.

10. The I-Q transmitter of claim 9 , wherein the modulation circuit further comprises,

a first mixer circuit configured to up convert the processed quantized in-phase signal from the first DAC component based on the first phase corrected LO signal, and

a second mixer circuit configured to up convert the processed quantized quadrature signal from the second DAC component based on the second phase corrected LO signal.

11. The I-Q transmitter of claim 1 , wherein the I-Q quantization circuit is configured to generate the quantized in-phase signal and the quantized quadrature signal by choosing a constellation point corresponding to the second I-Q pair from a predefined set of constellation points in an I-Q constellation diagram defined based on the resolution information of the DAC in the signal path of the quantized in-phase and quadrature signals.

12. A hybrid polar in-phase quadrature (I-Q) transmitter, comprising:

a quantization circuit configured to,

receive an in-phase signal and a quadrature signal forming a first I-Q data pair, and generate a quantized in-phase signal and a quantized quadrature signal forming a second I-Q data pair, respectively, based on a resolution information of a digital-to-analog converter (DAC) in a signal path of the quantized in-phase and quadrature signals;

wherein the first and the second I-Q data pairs form a point in an I-Q constellation diagram, and

a phase correction circuit to minimize a quantization error associated with the DAC, coupled to the quantization circuit and configured to,

determine a first rotation angle based on the first I-Q data pair and the second I-Q data pair, and

determine a second rotation angle based on the first I-Q data pair and the second I-Q data pair;

a synthesizer circuit configured to,

generate a first phase corrected local oscillator (LO) signal with an added first correction phase, wherein the first correction phase corresponds to the determined first rotation angle; and

generate a second phase corrected local oscillator (LO) signal with an added second correction phase, wherein the second correction phase corresponds to the determined second rotation angle; and

a modulation circuit configured to,

up convert the quantized in-phase signal based on the first phase corrected LO signal, and

up convert the quantized quadrature signal based on the second phase corrected LO signal.

13. The I-Q transmitter of claim 12 , wherein the first rotation angle is determined in accordance with a first predetermined relation between the first I-Q data pair and the second I-Q data pair, and the second rotation angle is determined in accordance with a second, different predetermined relation between the first I-Q data pair and the second I-Q data pair.

14. The I-Q transmitter of claim 12 , wherein the synthesizer circuit further comprises a first digital-to-time converter (DTC) to generate the first phase corrected LO signal and a second DTC to generate the second phase corrected LO signal.

15. The I-Q transmitter of claim 12 , further comprising a summation circuit configured to generate a final radio frequency (RF) output signal based on the up converted quantized in-phase signal and the up converted quantized quadrature signal.

16. A method for a hybrid polar in-phase quadrature (I-Q) transmitter, comprising:

receiving an in-phase signal and a quadrature signal forming a first I-Q data pair, and generating a quantized in-phase signal and a quantized quadrature signal forming a second I-Q data pair, respectively, based thereon using a quantization circuit;

wherein the first and the second I-Q data pairs form a point in an I-Q constellation diagram;

determining a first rotation angle and determining a second rotation angle based on the first I-Q data pair and the second I-Q data pair, using a phase correction circuit;

generating a first phase corrected local oscillator (LO) signal with an added first correction phase, based on the determined first rotation angle and generating a second phase corrected local oscillator (LO) signal with an added second correction phase, based on the determined second rotation angle using a synthesizer circuit; and

up converting the quantized in-phase signal and the quantized quadrature signal based on the first phase corrected LO signal and the second phase corrected LO signal, respectively, using a modulation circuit.

17. The method of claim 16 , further comprising processing the quantized in-phase signal and the quantized quadrature signal at a digital to analog converter (DAC) circuit within the modulation circuit, prior to up converting the quantized in-phase signal and the quantized quadrature signal.

18. The method of claim 16 , wherein generating the quantized in-phase signal and the quantized quadrature signal using the quantization circuit comprises choosing a constellation point corresponding to the second I-Q pair from a predefined set of constellation points in the I-Q constellation diagram defined based on a resolution information of a DAC in a signal path of the quantized in-phase and quadrature signals.

19. The method of claim 17 , further comprising generating a radio frequency (RF) output signal based on the up converted quantized in-phase signal and the up converted quantized quadrature signal, using a summation circuit.

20. The method of claim 17 , wherein the first rotation angle corresponds to an angle by which an I-axis of the I-Q constellation diagram is rotated to form a derived I-axis and the second rotation angle corresponds to an angle by which a Q-axis of the I-Q constellation diagram is rotated to form a derived Q-axis, in order to minimize a quantization error associated with the DAC.