System and method for in-phase/quadrature-phase (I/Q) time delay measurement and compensation

1. A system for determining a time delay between an in-phase signal component and a quadrature-phase signal component, comprising:

an in-phase signal start time determination module coupled to an in-phase delay module, the in-phase signal start time determination module and the in-phase delay module configured to receive an in-phase signal component of a received signal, and wherein the in-phase signal start time determination module is configured to receive a reference signal;

a quadrature-phase signal start time determination module coupled to a quadrature-phase delay module, the quadrature-phase signal start time determination module and the quadrature-phase delay module configured to receive a quadrature-phase signal component of a received signal, and wherein the quadrature-phase signal start time determination module is configured to receive a reference signal,

wherein the in-phase signal start time determination module is configured to develop an in-phase start time signal and the quadrature-phase signal start time determination module is configured to develop a quadrature-phase start time signal; and

wherein the in-phase delay module develops an in-phase delay signal representative of a delay of the in-phase signal component of the received signal and wherein the quadrature-phase delay module develops a quadrature-phase delay signal representative of a delay of the quadrature-phase signal component of the received signal.

2. The system of claim 1 , wherein the reference signal comprises a saved portion of a transmit signal.

3. The system of claim 1 , wherein the reference signal is a generated test signal.

4. The system of claim 1 , wherein the reference signal comprises an in-phase component and a quadrature-phase component.

5. The system of claim 1 , in which the system is implemented in a synchronizer of a receiver.

6. The system of claim 1 , further comprising using the in-phase delay signal to compensate for the delay of the in-phase signal component of the received signal and using the quadrature-phase delay signal to compensate for delay in the quadrature-phase signal component of the received signal.

7. A system for determining and compensating a time delay between an in-phase signal component and a quadrature-phase signal component, comprising:

an in-phase signal start time determination module configured to receive an in-phase signal component of a received signal, and wherein the in-phase signal start time determination module is configured to receive a reference signal;

a quadrature-phase signal start time determination module configured to receive a quadrature-phase signal component of a received signal, and wherein the quadrature-phase signal start time determination module is configured to receive the reference signal,

wherein the in-phase signal start time determination module is configured to develop an in-phase start time signal and the quadrature-phase signal start time determination module is configured to develop a quadrature-phase start time signal;

a subtractor configured to subtract the quadrature-phase start time signal from the in-phase start time signal to develop a net delay signal, wherein the net delay signal is applied to a baseband demodulator to compensate for received signal delay.

8. The system of claim 7 , wherein the reference signal comprises a saved portion of a transmit signal.

9. The system of claim 7 , wherein the reference signal is a generated test signal.

10. The system of claim 7 , wherein the reference signal comprises an in-phase component and a quadrature-phase component.

11. The system of claim 7 , in which the in-phase signal start time determination module further comprises:

first and second cross correlators configured to receive the in-phase signal component of the received signal, the first cross correlator configured to receive an in-phase reference signal, the second cross correlator configured to receive a quadrature-phase reference signal;

a first absolute value module configured to receive an output of the first cross correlator;

a second absolute value module configured to receive an output of the second cross correlator;

an adder configured to combine an output of the first cross correlator with an output of the second cross correlator; and

a magnitude determination module configured to determine the maximum magnitude of the in-phase delay signal and the quadrature-phase delay signal.

12. A method for determining a time delay between an in-phase signal component and a quadrature-phase signal component, comprising:

providing an in-phase signal component of a received signal to an in-phase signal start time determination module and to an in-phase delay module;

providing a reference signal to the in-phase signal start time determination module;

providing a quadrature-phase signal component of a received signal to a quadrature-phase signal start time determination module and to a quadrature-phase delay module;

providing the reference signal to the quadrature-phase signal start time determination module;

developing an in-phase start time and a quadrature-phase start time; and

determining an in-phase delay signal representative of a delay of the in-phase signal component of the received signal and determining a quadrature-phase delay signal representative of a delay of the quadrature-phase signal component of the received signal responsive to the in-phase start time and the quadrature-phase start time.

13. The method of claim 12 , wherein the reference signal comprises a saved portion of a transmit signal.

14. The method of claim 12 , wherein the reference signal is a generated test signal.

15. The method of claim 12 , wherein the reference signal comprises an in-phase component and a quadrature-phase component.

16. The method of claim 12 , in which the system is implemented in a synchronizer of a receiver.

17. The method of claim 12 , further comprising:

using the in-phase delay signal to compensate for the delay of the in-phase signal component of the received signal; and

using the quadrature-phase delay signal to compensate for delay in the quadrature-phase signal component of the received signal.

18. A system for determining a time delay between an in-phase signal component and a quadrature-phase signal component, comprising:

an in-phase signal start time determination module coupled to an in-phase delay module, the in-phase signal start time determination module and the in-phase delay module configured to receive an in-phase signal component of a received signal, and wherein the in-phase signal start time determination module is configured to receive a reference signal;

a quadrature-phase signal start time determination module coupled to a quadrature-phase delay module, the quadrature-phase signal start time determination module and the quadrature-phase delay module configured to receive a quadrature-phase signal component of a received signal, and wherein the quadrature-phase signal start time determination module is configured to receive a reference signal, wherein the in-phase signal start time determination module and the quadrature-phase signal start time determination module further comprise:

first and second cross correlators configured to receive the in-phase signal component of the received signal, the first cross correlator configured to receive an in-phase reference signal, the second cross correlator configured to receive a quadrature-phase reference signal; a first absolute value module configured to receive an output of the first cross correlator; a second absolute value module configured to receive an output of the second cross correlator; an adder configured to combine an output of the first cross correlator with an output of the second cross correlator; and

a magnitude determination module configured to determine the maximum magnitude of the in-phase delay signal and the quadrature-phase delay signal;

wherein the in-phase signal start time determination module is configured to develop an in-phase start time signal and the quadrature-phase signal start time determination module is configured to develop a quadrature-phase start time signal; and

wherein the in-phase delay module develops an in-phase delay signal representative of a delay of the in-phase signal component of the received signal and wherein the quadrature-phase delay module develops a quadrature-phase delay signal representative of a delay of the quadrature-phase signal component of the received signal.