IMPEDANCE BALANCING FOR TRANSMITTER TO RECEIVER REJECTION

• US 20130109330A1
• Filed: 10/26/2011
• Published: 05/02/2013
• Est. Priority Date: 10/26/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sahota, Gurkanwal Singh, Bossu, Frederic, Cetinoneri, Berke
• Granted Patent: US 9,083,441 B2
• Time in Patent Office: Days
• US Class Current: 455/77
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver
• CPC Class Codes: H04B 1/581 using a transformer

Abstract

Exemplary embodiments are directed to impedance balancing within a transceiver. A device may include a transformer having a first side coupled to a transmit path and a second side coupled to a receive path. Further, the device may include an antenna tuning network coupled to a first portion of the first side and configured for coupling to an antenna. The device may also include an adjustment unit coupled to a second portion of the first side and configured for being adjusted to enable an impedance at the adjustment unit to be substantially equal to an impedance at the antenna tuning network.

Claims

1. A transceiver, comprising:

a transformer having a first side coupled to a transmit path and a second side coupled to a receive path;

an antenna tuning network coupled to a first portion of the first side and configured for coupling to an antenna; and

an adjustment unit coupled to a second portion of the first side and configured for being adjusted to enable an impedance at the adjustment unit to be substantially equal to an impedance at the antenna tuning network.

2. The transceiver of claim 1, further comprising an antenna impedance sensor and control unit coupled to each of the antenna tuning network and the adjustment unit and configured for sensing an impedance at the antenna tuning network.

3. The transceiver of claim 1, the first side of the transformer comprising a primary side and the second side of the transformer comprising a secondary side.

4. The transceiver of claim 1, the transmit path coupled to a center port of a primary side of the transformer and the receive path coupled to a secondary side of the transformer.

5. The transceiver of claim 1, further comprising signal processing circuitry coupled between the receive path and the adjustment unit and configured to measure an amount of transmit leakage at an input of the receive path.

6. The transceiver of claim 5, the signal processing circuitry further configured to convey at least one signal to the adjustment unit to enable for adjustment thereof.

7. A transceiver, comprising:

at least one transformer including;

a primary side coupled to each of a replica port and a transmit path and configured for coupling to an antenna; and

a secondary side coupled to each of a receive path and the replica port, the replica port coupled to at least one adjustable component and configured for transmit signal leakage cancellation.

8. The transceiver of claim 7, the at least one transformer including:

a first transformer having a primary side and a secondary side, the primary side of the first transformer coupled to each of the transmit path and the replica port and configured for coupling to the antenna; and

a second transformer having a primary side and a secondary side, the primary side of the second transformer coupled to the secondary side of the first transformer, the secondary side of the second transformer coupled to each of the replica port and the receive path.

9. The transceiver of claim 8, further comprising a feedforward path coupled between the replica port and the receive path and including the at least one adjustable element.

10. The transceiver of claim 7, the at least one adjustable element coupled between the replica port and a ground voltage.

11. The transceiver of claim 10, further comprising a capacitor coupled to the secondary side of the at least on transformer and configured for common-mode cancellation.

12. The transceiver of claim 7, further comprising a feedforward path coupled between the replica port and the receive path and including the at least one adjustable element.

13. A method, comprising:

sensing an impedance at an antenna port coupled to a first portion of a transformer; and

adjusting an impedance at an adjustment port coupled to a second portion of the transformer to substantially match the impedance at the antenna port with the impedance at the adjustment port.

14. The method of claim 13, the sensing comprising sensing the impedance at the antenna port coupled to the first portion of a primary side of a first transformer.

15. The method of claim 14, the adjusting comprising adjusting the impedance at the adjustment port coupled to the second portion of the primary side of the first transformer.

16. The method of claim 13, further comprising sensing an amount of transmit leakage at a receive path coupled to a third portion of the transformer.

17. The method of claim 16, further comprising further adjusting the adjustment port in response to sensing the amount of transmit leakage at the receive path.

18. The method of claim 13, further comprising:

sensing an amount of transmit leakage at a diversity receive path coupled to a portion of a second transformer coupled to the first transformer via the adjustment port; and

adjusting a diversity adjustment port coupled to another portion of the second transformer in response to sensing the amount of transmit leakage at the diversity receive path.

19. A transceiver, comprising:

an antenna tuning network coupled to a first port of a first transformer and for coupling to a primary antenna;

a first balancing network coupled to each of a second port of the first transformer and a first port of a second transformer; and

a second balancing network coupled to a second port of the second transformer, the second transformer configured for coupling to a diversity antenna.

20. The transceiver of claim 19, further comprising at least one controller configured for:

sensing an impedance at the antenna tuning network;

sensing a transmit signal on a receive path coupled to the first transformer;

sensing a transmit signal on a receive path coupled to the second transformer; and

adjusting at least one of the first balancing network and the second balancing network.

21. The transceiver of claim 19, further comprising signal processing circuitry configured to measure transmit leakage associated with at least one of the first transformer and the second transformer.

22. A method, comprising:

measuring a transmit signal on a receive path coupled to a transformer; and

adjusting an adjustment unit coupled to the transformer to at least partially cancel the transmit signal on the receive path.

23. The method of claim 22, the measuring comprising measuring transmit leakage on the receive path coupled to a secondary side of the transformer.

24. The method of claim 22, the adjusting comprising adjusting the adjustment unit coupled to a primary side of the first transformer.

25. The method of claim 22, the adjusting comprising adjusting at least one of a phase of the adjustment unit and an amplitude of the adjustment unit to at least partially cancel the transmit signal on the receive path.

26. A device, comprising:

means for sensing an impedance at an antenna port coupled to a first portion of a transformer; and

means for adjusting an impedance at an adjustment unit coupled to a second portion of the transformer to substantially match the impedance at the antenna port with the impedance at the adjustment unit.

27. A device, comprising:

means for measuring a transmit signal on a receive path coupled to a transformer; and

means for adjusting an adjustment unit coupled to the transformer to at least partially cancel the transmit signal on the receive path.