Patent ID: 7599618

Claim:
A method of self-testing a tester, which includes a controller, a transmitter and a receiver, the method comprising: a) conducting baseline tests of the tester including: transmitting a plurality of test signals from the transmitter to at least one device under test, each test signal at a different power level; receiving the test signals from the device under test at the recevier; determining the power level of each test signal; determining a BER for each test signal; determining a baseline sensitivity of the receiver, defined by a minimum power level of test signal that the receiver requires to achieve a minimum BER limit; b) storing the baseline sensitivity in a database accessible by the controller; c) conducting self tests of the tester at periodic intervals including: connecting the transmitter to the receiver via a loop-back connection; transmitting a plurality of self-test signals from the transmitter, each self-test signal at a different power level; receiving the plurality of self-test signals at the receiver via the loop back connection; determining the power level of each self-test signal; determining a BER for each self-test signal; determining the sensitivity of the receiver at the periodic intervals by determining a minimum power level of test signal that the receiver requires to achieve a desired BER; comparing the sensitivity at the periodic intervals with the baseline sensitivity previously stored in the database; and d) determining when recalibration of the tester is required based on the difference in sensitivity at each time interval and the baseline sensitivity.