Tranceiver circuit for compensating IQ mismatch and carrier leakage and method for controlling the same

• US 20070202812A1
• Filed: 02/21/2007
• Published: 08/30/2007
• Est. Priority Date: 02/23/2006
• Status: Active Grant

• Current Assignee: GCT Semiconductor Incorporated
• Original Assignee: GCT Semiconductor Incorporated
• Inventors: Lee, Kyeongho, Park, Joonbae
• Granted Patent: US 7,831,215 B2
• Time in Patent Office: Days
• US Class Current: 455/75
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver

Abstract

Embodiments of methods, transceiver circuits, and systems can compensate an IQ mismatch (e.g., Tx or Rx) or a carrier leakage using a plurality of local oscillators. One embodiment of a transceiver can include a first up-conversion IQ mixer, a second up-conversion IQ mixer, a first down-conversion IQ mixer with an input to receive an output of the second up-conversion IQ mixer, a second down-conversion IQ mixer with an input to receive an output of the first up-conversion IQ mixer, a first local oscillator to generate a first IQ LO signal for the first up-conversion IQ mixer and the first down-conversion IQ mixer, and a second local oscillator to generate a second IQ LO signal for the second up-conversion IQ mixer and the second down-conversion IQ mixer.

Claims

1. A method for controlling a transceiver circuit comprising a first up-conversion IQ mixer, a second up-conversion IQ mixer, a first down-conversion IQ mixer, a second down-conversion IQ mixer, a first local oscillator and a second oscillator, the method comprising:

(a) measuring a Tx carrier leakage using a signal obtained by passing a Tx carrier leakage included in an output of the first up-conversion IQ mixer through the second down-conversion IQ mixer;

(b) measuring a Tx IQ mismatch using a signal being passed through the first up-conversion IQ mixer and the second down-conversion IQ mixer;

(c) measuring a Rx IQ mismatch using a signal being passed through the second up-conversion IQ mixer and the first down-conversion IQ mixer; and

(d) carrying out transmission/reception using the first up-conversion IQ mixer and the first down-conversion IQ mixer during an operation period,

wherein the first local oscillator generates a first IQ LO signal used in the first up-conversion IQ mixer and the first down-conversion IQ mixer, and the second oscillator generates a second IQ LO signal used in the second up-conversion IQ mixer and the second down-conversion IQ mixer.

2. The method in accordance with claim 1, wherein the first up-conversion IQ mixer and the second down-conversion IQ mixer are operational and the second up-conversion IQ mixer and the first down-conversion IQ mixer are non-operational in the steps (a) and (b),

wherein the second up-conversion IQ mixer and the first down-conversion IQ mixer are operational and the first up-conversion IQ mixer and the second down-conversion IQ mixer are non-operational in the step (c),

wherein the first up-conversion IQ mixer is operational and the first down-conversion IQ mixer, the second up-conversion IQ mixer and the second down-conversion IQ mixer are non-operational during a transmission period of the operation period, and

wherein the first down-conversion IQ mixer is operational and the first up-conversion IQ mixer, the second up-conversion IQ mixer and the second down-conversion IQ mixer are non-operational during a reception period of the operation period.

3. The method in accordance with claim 1, wherein frequencies of the first IQ LO signal and the second IQ LO signal are different.

4. The method in accordance with claim 1, wherein a power of a signal inputted to the first up-conversion IQ mixer in the step (a) substantially has a value of zero,

wherein a signal inputted to the first up-conversion IQ mixer in the step (b) has a first prescribed frequency, and signals of I and Q channels of the signal inputted to the first up-conversion IQ mixer have a prescribed first power, and

wherein a signal inputted to the second up-conversion IQ mixer in the step (c) has a second prescribed frequency, and signals of I and Q channels of the signal inputted to the first up-conversion IQ mixer have a prescribed second power.

5. The method in accordance with claim 1, wherein signals of I and Q channels of a signal inputted to the first up-conversion IQ mixer have a phase difference of 90°

in the step (b), wherein signals of I and Q channels of a signal inputted to the second up-conversion IQ mixer have a phase difference of 90°

in the step (c), wherein the transceiver circuit is a TDD type transceiver circuit, and wherein the steps (a) through (c) are performed when the receiving circuit is turned on, temperature of the receiving circuit is out of a prescribed range or transitions through a prescribed threshold or a voltage supplied to the receiving circuit is out is out of a prescribed range or transitions through a prescribed threshold.

6. The method in accordance with claim 1, wherein a signal inputted to the first up-conversion IQ mixer in the step (b) comprises a signal having the Tx carrier leakage compensated for, and

wherein a signal inputted to the first up-conversion IQ mixer during the operation period comprises a signal having the Tx carrier leakage and the Tx IQ mismatch compensated for, and a signal outputted by the first down-conversion IQ mixer has the Rx IQ mismatch compensated for after being converted to a digital signal.

7. A method for controlling a transceiver circuit comprising a first up-conversion IQ mixer, a first down-conversion IQ mixer, a second down-conversion IQ mixer, a first local oscillator and a second oscillator, the method comprising:

measuring a Tx carrier leakage using a signal obtained by passing a Tx carrier leakage included in an output of the first up-conversion IQ mixer through the second down-conversion IQ mixer; and

performing transmission/reception using the first up-conversion IQ mixer and the first down-conversion IQ mixer during an operation period,

wherein the first local oscillator generates a first IQ LO signal used in the first up-conversion IQ mixer and the first down-conversion IQ mixer, and the second oscillator generates a second IQ LO signal used in the second down-conversion IQ mixer.

8. The method in accordance with claim 7, wherein the first up-conversion IQ mixer and the second down-conversion IQ mixer are operational and the first down-conversion IQ mixer is non-operational when measuring said Tx carrier leakage,

wherein the first up-conversion IQ mixer is operational and the first down-conversion IQ mixer and the second down-conversion IQ mixer are non-operational during a transmission period of the operation period, and

wherein the first down-conversion IQ mixer is operational and the first up-conversion IQ mixer and the second down-conversion IQ mixer are non-operational during a reception period of the operation period, and wherein frequencies of the first IQ LO signal and the second IQ LO signal are different.

9. A method for controlling a transceiver circuit comprising a first up-conversion IQ mixer, a first down-conversion IQ mixer, a second down-conversion IQ mixer, a first local oscillator and a second oscillator, the method comprising:

measuring a Tx IQ mismatch using a signal being passed through the first up-conversion IQ mixer and the second down-conversion IQ mixer;

carrying out a TDD type transmission/reception using the first up-conversion IQ mixer and the first down-conversion IQ mixer during a normal operation period,

wherein the first local oscillator generates a first IQ LO signal used in the first up-conversion IQ mixer and the first down-conversion IQ mixer, and the second oscillator generates a second IQ LO signal used in the second down-conversion IQ mixer.

10. The method in accordance with claim 9, wherein the first up-conversion IQ mixer and the second down-conversion IQ mixer are operational and the first down-conversion IQ mixer is non-operational when measuring said Tx IQ mismatch,

wherein the first up-conversion IQ mixer is operational and the first down-conversion IQ mixer and the second down-conversion IQ mixer are non-operational during a transmission period of the normal operation period, and

wherein the first down-conversion IQ mixer is operational and the first up-conversion IQ mixer and the second down-conversion IQ mixer are non-operational during a reception period of the normal operation period, and wherein frequencies of the first IQ LO signal and the second IQ LO signal are different.

11. A method for controlling a transceiver circuit comprising a first up-conversion IQ mixer, a second up-conversion IQ mixer, a first down-conversion IQ mixer, a first local oscillator and a second oscillator, the method comprising:

measuring a Rx IQ mismatch using a signal being passed through the second up-conversion IQ mixer and the first down-conversion IQ mixer;

carrying out a transmission/reception using the first up-conversion IQ mixer and the first down-conversion IQ mixer during an operation period,

generating a first IQ LO signal used in the first up-conversion IQ mixer and the first down-conversion IQ mixer using the first local oscillator; and

generating a second IQ LO signal used in the second up-conversion IQ mixer using the second oscillator.

12. The method in accordance with claim 11, wherein the second up-conversion IQ mixer and the first down-conversion IQ mixer are operational and the first up-conversion IQ mixer is non-operational when measuring said Rx IQ mismatch,

wherein the first up-conversion IQ mixer is operational and the first down-conversion IQ mixer and the second up-conversion IQ mixer are non-operational during a transmission period of the operation period, and

wherein the first down-conversion IQ mixer is operational and the first up-conversion IQ mixer and the second up-conversion IQ mixer are non-operational during a reception period of the normal operation period, and wherein frequencies of the first IQ LO signal and the second IQ LO signal are different.

13. A transceiver circuit, comprising:

a first up-conversion IQ mixer;

a second up-conversion IQ mixer;

a first down-conversion IQ mixer with an input to receive an output of the second up-conversion IQ mixer;

a second down-conversion IQ mixer with an input to receive an output of the first up-conversion IQ mixer;

a first local oscillator to generate a first IQ LO signal coupled to the first up-conversion IQ mixer and the first down-conversion IQ mixer; and

a second local oscillator to generate a second IQ LO signal coupled to the second up-conversion IQ mixer and the second down-conversion IQ mixer.

14. The circuit in accordance with claim 13, further comprising:

an IQ DAC having an output respectively coupled to an input of the first up-conversion IQ mixer and the second up-conversion IQ mixer;

an IQ filter coupled to receive outputs of the first down-conversion IQ mixer and the second down-conversion IQ mixer;

a IQ ADC coupled to receive an output of the IQ filter;

a power amplifier to receive the output of the first up-conversion IQ mixer;

a low noise amplifier with an output coupled to an input of the first down-conversion IQ mixer; and

a duplexer to transceive an RF signal with an antenna, wherein the duplexer is coupled to receive a transmission RF signal from the power amplifier and output a received RF signal to the low noise amplifier.

15. The circuit in accordance with claim 14, further comprising:

a multiplexer to select and output one of a transmission signal corresponding to the transmission RF signal and a test signal;

a Tx compensator configured to receive an output of the multiplexer to compensate a Tx carrier leakage and a Tx IQ mismatch of a signal received according to a Tx carrier leakage control signal and a Tx IQ mismatch control signal and output the compensated signal to the IQ DAC;

a Rx IQ mismatch compensator configured to receive an output of the IQ ADC to compensate a Rx IQ mismatch of a signal received according to a Rx IQ mismatch control signal; and

a controller configured to generate the test signal, to receive the output of the IQ ADC to measure the Tx carrier leakage, the Tx IQ mismatch and the Rx IQ mismatch, and to generate the Tx carrier leakage control signal, the Tx IQ mismatch control signal and the Rx IQ mismatch control signal.

16. The circuit in accordance with claim 13, wherein frequencies of the first IQ LO signal and the second IQ LO signal are different.

17. The circuit in accordance with claim 13, wherein the first up-conversion IQ mixer and the second down-conversion IQ mixer are operational, and the second up-conversion IQ mixer and the first down-conversion IQ mixer are non-operational during a period of measuring the Tx carrier leakage.

18. The circuit in accordance with claim 17, wherein a power of a signal inputted to the first up-conversion IQ mixer during the period of measuring the Tx carrier leakage is zero.

19. The circuit in accordance with claim 13, wherein the first up-conversion IQ mixer and the second down-conversion IQ mixer are operational, and the second up-conversion IQ mixer and the first down-conversion IQ mixer are non-operational when measuring the Tx IQ mismatch.

20. The circuit in accordance with claim 19, wherein the Tx carrier leakage is compensated for a signal inputted to the first up-conversion IQ mixer when the Tx IQ mismatch is measured.

21. The circuit in accordance with claim 13, wherein the second up-conversion IQ mixer and the first down-conversion IQ mixer are operational, and the first up-conversion IQ mixer and the second down-conversion IQ mixer are non-operational during a period of measuring the Rx IQ mismatch.

22. The circuit in accordance with claim 13, wherein the second up-conversion IQ mixer and the second down-conversion IQ mixer are non-operational, and the first up-conversion IQ mixer and the first down-conversion IQ mixer are respectively used to perform a TDD type transmission/reception operation.