Antenna interface circuit, data card, and antenna connection control method and apparatus

1. A circuit, comprising:

a main connector having a common contact, a normally-closed contact, and a normally-open contact; and

a single-pole double-throw switch having a common contact, a normally-closed contact, and a normally-open contact, wherein:

the common contact of the main connector is used as a terminal of a main receiver;

the normally-closed contact of the main connector is used as a port of a main antenna;

the normally-open contact of the main connector is used as a port of an external antenna;

the common contact of the single-pole double-throw switch is used as a port of a diversity receiver;

the normally-closed contact of the single-pole double-throw switch is used as a port of a diversity antenna; and

the normally-open contact of the single-pole double-throw switch is connected to the normally-closed contact of the main connector.

2. The circuit according to claim 1 , wherein when the common contact of the main connector is connected to the normally-open contact of the main connector, the common contact of the single-pole double-throw switch is connected to the normally-open contact of the single-pole double-throw switch.

3. The circuit according to claim 2 , wherein the diversity antenna is communicatively decoupled from the diversity receiver.

4. The circuit according to claim 1 , wherein when the common contact of the main connector is not connected to the normally-open contact of the main connector, the common contact of the single-pole double-throw switch is connected to the normally-closed contact of the single-pole double-throw switch.

5. The circuit according to claim 4 , wherein the common contact of the main connector is connected to the normally-closed contact of the main connector.

6. The circuit according to claim 4 , wherein the diversity receiver is communicatively decoupled from the main antenna.

7. The circuit according to claim 1 , further comprising a single-pole single-throw switch arranged between the main antenna and the normally-open contact of the single-pole double-throw switch, wherein the normally-open contact of the single-pole double-throw switch is connected to the normally-closed contact of the main connector via the single-pole single-throw switch, and wherein the single-pole single-throw switch is closed when the common contact of the main connector is connected to the normally-open contact of the main connector.

8. A circuit, comprising:

a main connector comprising a first single-pole double-throw switch and a second single-pole double-throw switch, wherein:

a common contact of the main connector is coupled to a port of a main receiver;

a normally-open contact of the main connector is coupled to a port of an external antenna;

a normally-closed contact of the main connector is connected to a normally-closed contact of the first single-pole double-throw switch, and a common contact of the first single-pole double-throw switch is coupled to a port of a main antenna;

a common contact of the second single-pole double-throw switch is coupled to a port of a diversity receiver;

a normally-closed contact of the second single-pole double-throw switch is coupled to a port of a diversity antenna;

a normally-open contact of the second single-pole double-throw switch is connected to a normally-open contact of the first single-pole double-throw switch; and

when the common contact of the main connector is connected to the normally-open contact of the main connector, the common contact of the first single-pole double-throw switch is connected to the normally-open contact of the first single-pole double-throw switch, and the common contact of the second single-pole double-throw switch is connected to the normally-open contact of the second single-pole double-throw switch.

9. The circuit according to claim 8 , wherein when the common contact of the main connector is not connected to the normally-open contact of the main connector, the common contact of the first single-pole double-throw switch is connected to the normally-closed contact of the first single-pole double-throw switch, and the common contact of the second single-pole double-throw switch is connected to the normally-closed contact of the second single-pole double-throw switch.

10. A data card comprising:

an antenna interface circuit comprising a main connector and a single-pole double-throw switch, wherein:

a common contact of the main connector is used as a terminal of a main receiver;

a normally-closed contact of the main connector is used as a port of a main antenna;

a normally-open contact of the main connector is used as a port of an external antenna;

a common contact of the single-pole double-throw switch is used as a port of a diversity receiver;

a normally-closed contact of the single-pole double-throw switch is used as a port of a diversity antenna;

a normally-open contact of the single-pole double-throw switch is connected to the normally-closed contact of the main connector; and

when the common contact of the main connector is connected to the normally-open contact of the main connector, the common contact of the single-pole double-throw switch is connected to the normally-open contact of the single-pole double-throw switch.

11. The data card according to claim 10 , wherein when the common contact of the main connector is not connected to the normally-open contact of the main connector, the common contact of the single-pole double-throw switch is connected to the normally-closed contact of the single-pole double-throw switch.

12. The data card according to claim 10 , wherein the antenna interface circuit further comprises a single-pole single-throw switch, wherein the normally-open contact of the single-pole double-throw switch is connected to the normally-closed contact of the main connector via the single-pole single-throw switch, and wherein when the common contact of the main connector is connected to the normally-open contact of the main connector, the single-pole single-throw switch is closed.

13. A method, comprising:

determining whether a main receiver is connected to an external antenna through a connector; and

controlling, based on the determination, a connection between a diversity receiver and a main antenna using a single-pole double-throw switch, wherein the connector isolates the external antenna from the diversity receiver when the diversity receiver is connected to the main antenna.

14. The method according to claim 13 , further comprising:

controlling the single-pole double-throw switch to connect the diversity receiver to a diversity antenna, different from the main antenna, when the main receiver is not connected to the external antenna.

15. The method according to claim 14 , wherein the main receiver is coupled to the main antenna.

16. The method according to claim 13 , further comprising:

controlling the single-pole double-throw switch to couple the diversity receiver to the main antenna when the main receiver is connected to the external antenna.

17. An apparatus, comprising:

a detector configured to detect whether a main receiver is connected to an external antenna; and

a controller configured to control, when the main receiver is connected to the external antenna, a diversity receiver to connect to a main antenna through a single-pole double-throw switch, wherein the single-pole double-throw switch does not provide a connection path between the diversity receiver and the external antenna.

18. The apparatus according to claim 17 , wherein the controller is further configured to control, when the main receiver is not connected to the external antenna, the single-pole double-throw switch to connect to the diversity receiver and a diversity antenna.