Tester

A system, comprising:

• a tester comprising a source and measuring device;
• and
• an extension circuit comprising a TX (transmission) port connected to the tester, a termination switch and a calibration device that provides one or more terminations, wherein each of the terminations is individually connectable to the TX port by the termination switch,
• wherein the calibration device comprises a power sensor,
• wherein one of the terminations is the power sensor, which is configured to measure a power of the source and measuring device at the TX port,
• wherein the source and measuring device is configured to measure one or more reflection coefficients at the TX port for the one or more terminations provided by the calibration device, and
• wherein the tester is configured to determine a source reflection coefficient by using the one or more measured reflection coefficients.

A method of determining a source reflection coefficient, the method comprising:

• connecting a TX (transmission) port of an extension circuit to a source and measuring device, wherein the extension circuit comprises a termination switch and a calibration device that provides one or more terminations, wherein each of the terminations is individually connectable to the TX port by the termination switch, wherein the calibration device comprises a power sensor, wherein one of the terminations is the power sensor, which is configured to measure a power of the source and measuring device at the TX port;
• measuring one or more reflection coefficients at the TX port for the one or more terminations provided by the calibration device;
• and
• determining the source reflection coefficient of the source and measuring device based on the one or more measured reflection coefficients.