Tester

1. An apparatus, comprising:

a tester configured to connect to an extension circuit and comprising:

a source and measuring device including a source power; and

a TX (transmission) port connected to the source and measuring device;

wherein the tester is configured to determine a source reflection coefficient of the source and measuring device by using the extension circuit, wherein the extension circuit comprises a calibration device comprising a power sensor; and

wherein the tester is configured to calibrate the source power of the source and measuring device using the determined source reflection coefficient and the power sensor.

2. The apparatus according to claim 1 , wherein the tester is configured to derive a power value at a port of the extension circuit using known parameters of the extension circuit.

3. The apparatus according to claim 2 , wherein the known parameters of the extension circuit comprise at least one of

reflection S parameters of the extension circuit; or

transmission S parameters of the extension circuit.

4. The apparatus according to claim 1 , wherein the calibration device is configured to provide a plurality of different terminations at the TX port, wherein the source and measuring device is configured to measure a plurality of reflection coefficients at the TX port for the plurality of different terminations provided by the calibration device at the TX port; and

wherein the tester is configured to determine the source reflection coefficient based on the measured reflection coefficients.

5. The apparatus according to claim 4 , wherein the tester is configured to determine the source reflection coefficient further based on known reflection coefficients of the extension circuit at the TX port.

6. The apparatus according to claim 1 , wherein the calibration device is configured to provide a plurality of different terminations at the TX port, wherein the tester is configured to calibrate the source power of the source and measuring device by acquiring a measured source power at the TX port using the power sensor of the calibration device of the extension circuit, and determining an actual source power available for a termination of the TX port with a reference impedance using the measured source power and the source reflection coefficient.

7. The apparatus according to claim 6 , wherein the tester is configured to determine a calibration factor for calibrating the source power based on the set source power set at the source and measuring device and the actual source power.

8. The apparatus according to claim 1 , wherein the tester further comprises:

a receiver including a receiver power and a power sensor; and

a RX (receiving) port connected to the receiver;

wherein the tester is configured to set up a loopback path connecting the TX port and the RX port via the extension circuit; and

wherein the tester is configured to calibrate the receiver power of the receiver using the calibrated source power and the power sensor of the receiver.

9. The apparatus according to claim 8 , wherein the tester is configured to determine a reflection coefficient presented by a receiver path to the extension circuit at the RX port by using a measured reflection coefficient measured at the TX port with the source and measuring device under the condition that the TX port is connected with the RX port and that the RX port is connected to the receiver path, and known parameters of the extension circuit, and to calibrate the receiver power further based on the determined reflection coefficient presented by the receiver path to the extension circuit at the RX port.

10. The apparatus according to claim 9 , wherein the tester is configured to calibrate the receiver power by using a calculated receiver power at the RX port that is calculated by using the determined reflection coefficient presented by the receiver path to the extension circuit at the RX port and known parameters of the extension circuit.

11. The apparatus according to claim 8 , wherein the tester is configured to derive a power input to the extension circuit from a device under test on the basis of a power value measured by the receiver of the tester.

12. A system, comprising:

a tester comprising:

a source and measuring device including a source power; and

a TX (transmission) port connected to the source and measuring device; and

an extension circuit comprising a calibration device comprising a power sensor;

wherein the tester and the extension circuit are connected via the TX port, and wherein the calibration device is configured to provide a plurality of different terminations at the TX port;

wherein the tester is configured to determine a source reflection coefficient of the source and measuring device by using the extension circuit; and

wherein the tester is configured to calibrate the source power of the source and measuring device using the determined source reflection coefficient and the power sensor.

13. The system according to claim 12 , wherein the tester further comprises a receiver and a RX (receiving) port connected to the receiver,

wherein the tester and the extension circuit are connected via the RX port, and wherein the extension circuit is configured to provide a loopback path by connecting the TX port and the RX port.

14. The system according to claim 12 , wherein the tester further comprises a receiver and a RX (receiving) port connected to the receiver,

wherein the extension circuit comprises at least one RF port configured to be connected to a device under test, and wherein the extension circuit is configured to connect the at least one RF port to the TX port and/or RX port.

15. The system according to claim 12 , wherein the tester further comprises a receiver and a RX (receiving) port connected to the receiver,

wherein the tester and the extension circuit are connected via the RX port, wherein the extension circuit comprises a switch matrix connected between the TX port, the RX port and at least one RF port configured to be connected to a device under test;

wherein in a first state the extension circuit is configured to provide a loopback path by connecting the TX port and the RX port; and

wherein in a second state the extension circuit is configured to connect the at least one RF port to the TX port and/or RX port.

16. The system according to claim 15 , wherein the extension circuit comprises a switch connected to the calibration device and connected between the TX port and the switch matrix;

wherein in the first state and the second state the extension circuit is configured to connect the TX port to the switch matrix; and

wherein in a third state the extension circuit is configured to connect the TX port to the calibration device.

17. The system according to claim 12 , wherein the tester further comprises a connection circuit including flexible cables,

wherein the tester is connected to the extension circuit via the flexible cables.

18. A method of calibrating a source power of a source and measuring device of a tester, the method comprising:

determining a source reflection coefficient of the source and measuring device by using an extension circuit, wherein the tester includes a TX (transmission) port connected to the source and measuring device, wherein the extension circuit comprises a calibration device comprising a power sensor, and wherein the calibration device is configured to provide a plurality of different terminations at the TX port; and

calibrating the source power of the source and measuring device using the determined source reflection coefficient and the power sensor of the calibration device.

19. The method according to claim 18 , wherein the tester and the extension circuit are connected via the TX port,

wherein the method further comprises: determining reflection S parameters and transmission S parameters of the extension circuit with a network analyzer before connecting the extension circuit to the tester to acquire known parameters of the extension circuit.