On-chip IQ imbalance and LO leakage calibration for transceivers

1. A method of autocalibrating a transceiver, comprising:

upconverting a bandpass input signal by mixing the bandpass input signal with a first local oscillator signal to form an initial transmitter signal;

looping back the initial transmitter signal to a receiver;

bypassing one of an inphase path and a quadrature path of the receiver;

downconverting the initial transmitter signal with a second local oscillator signal having a frequency that is different from the first local oscillator to form an intermediate frequency signal;

adjusting at least one of a gain and a phase of a transmitter based on a transmitter image sideband of the intermediate frequency signal to generate a calibrated transmitter signal having minimized transmitter image sideband;

injecting a test signal from at least one of the calibrated transmitter signal and a bandpass signal source into a complex receiver;

downconverting the test signal in a complex receiver to form a complex baseband signal by using the test signal with the first local oscillator; and adjusting at least one of a gain and a phase of the complex receiver based on a receiver image sideband of the complex baseband signal to generate a calibrated receiver signal having minimized receiver image sideband.

2. The method of claim 1 , wherein generating the calibrated transmitter signal having the minimized transmitter image sideband includes at least one of minimizing a transmitter image sideband power spectral density and transmitter image sideband power.

3. The method of claim 1 , further comprising:

separating the transmitter image sideband from the intermediate frequency signal;

separating a transmitter desired signal from the intermediate frequency signal; and

minimizing a power ratio of the transmitter image sideband to the transmitter desired signal.

4. The method of claim 1 , further comprising:

adjusting a DC offset of the transmitter based on a transmitter LO leakage of the intermediate frequency signal to generate the calibrated transmitter signal having minimized transmitter LO leakage.

5. The method of claim 4 , further comprising:

separating the transmitter LO leakage from the intermediate frequency signal;

separating a transmitter desired signal from the intermediate frequency signal; and

minimizing a power ratio of the transmitter LO leakage to the transmitter desired signal.

6. The method of claim 1 , wherein downconverting the test signal is performed on both an inphase complex receiver path and a quadrature complex receiver path simultaneously.

7. The method of claim 6 , further comprising:

digitally filtering the downconverted test signal with at least one of a digital FIR filter, a digital IIR filter, a discrete Fourier transform, and a fast Fourier transform to generate a receiver image sideband;

digitally filtering the complex baseband signal with at least one of a digital FIR filter, a digital IIR filter, a discrete Fourier transform, and a fast Fourier transform to generate a receiver desired signal; and

minimizing a power ratio of the receiver image sideband to the receiver desired signal.

8. The method of claim 6 , further comprising:

digitally filtering the complex baseband signal with at least one of a digital FIR filter, a digital IIR filter, a discrete Fourier transform, and a fast Fourier transform to generate a receiver LO leakage;

digitally filtering the complex baseband signal with at least one of a digital FIR filter, a digital IIR filter, a discrete Fourier transform, and a fast Fourier transform to generate a receiver desired signal; and

minimizing a power ratio of the receiver LO leakage to the receiver desired signal.

9. The method of claim 7 , further comprising:

adjusting at least one of the gain and the phase of the receiver based a minimization algorithm of a power ratio of a receiver image sideband power to the receiver desired signal.

10. The method of claim 8 , further comprising:

adjusting a DC offset of the receiver based on a minimization algorithm that minimizes a power ratio of the receiver LO leakage to the receiver desired signal.

11. A device for autocalibrating a transceiver, comprising:

an upconverter configured to mix a bandpass input signal with a first local oscillator signal to form an initial transmitter signal;

a bypass switch configured to bypass one of an inphase path and a quadrature path of a receiver of the transceiver;

the receiver configured to downconvert the initial transmitter signal with a second local oscillator signal having a frequency that is different from the first local oscillator to form an intermediate frequency signal;

a loop back circuit configured to route the initial transmitter signal to the receiver;

an adjuster circuit configured to adjust at least one of a gain and a phase of a transmitter based on a transmitter image sideband of the intermediate frequency signal to generate a calibrated transmitter signal having minimized transmitter image sideband;

a test signal source selector configured to select a test signal from at least one of the calibrated transmitter signal and a bandpass signal source; a complex receiver configured to downconvert the test signal by mixing the test signal with the first local oscillator to form a complex baseband signal; and an adjustment circuit configured to adjust at least one of a gain and a phase of the complex receiver based on a receiver image sideband of the complex baseband signal to generate a calibrated receiver signal having minimized receiver image sideband.

12. The device of claim 11 , wherein the adjuster circuit minimizes at least one of transmitter image sideband power spectral density and transmitter image sideband power.

13. The device of claim 11 , wherein the first local oscillator is at least one of an on-chip voltage controlled oscillator and a phase locked loop.

14. The device of claim 11 , further comprising:

a first digital filter configured to separate the transmitter image sideband from the intermediate frequency signal;

a reference digital filter configured to separate a transmitter desired signal from the intermediate frequency signal; and

a minimizer configured to minimize a power ratio of the transmitter image sideband to the transmitter desired signal.

15. The device of claim 11 , further comprising:

an adjustment circuit configured to adjust a DC offset of the transmitter based on a transmitter LO leakage of the intermediate frequency signal to generate the calibrated transmitter signal having minimized transmitter LO leakage.

16. The device of claim 15 , further comprising:

a transmitter LO leakage digital filter configured to separate the transmitter LO leakage from the intermediate frequency signal;

a reference digital filter configured to separate a transmitter desired signal from the intermediate frequency signal; and

a minimizer configured to minimize a power ratio of the transmitter LO leakage to the transmitter desired signal.

17. The device of claim 13 , wherein the complex receiver downconverts the test signal on both an inphase complex receiver path and a quadrature complex receiver path simultaneously.

18. The device of claim 14 further comprising:

a first digital filter configured to filter the complex baseband signal to generate a receiver image sideband;

a reference digital filter configured to filter the complex baseband signal to generate a receiver desired signal; and

a minimizer configured to minimize a power ratio of the receiver image sideband to the receiver desired signal.

19. The device of claim 17 , further comprising:

a receiver LO leakage digital filter configured to filter the complex baseband signal to generate a receiver LO leakage;

a reference digital filter configured to filter the complex baseband signal to generate a receiver desired signal; and

a minimizer configured to minimize a power ratio of the receiver LO leakage to the receiver desired signal.

20. The device of claim 17 , further comprising:

an adjuster configured to adjust at least one of the gain and the phase of the receiver based a minimization algorithm of a power ratio of a receiver image sideband power to a receiver desired signal.

21. The device of claim 19 , further comprising:

an adjuster configured to adjust a DC offset of the receiver based a minimization algorithm of a power ratio of the receiver LO leakage to the receiver desired signal.