Final answer:
To determine a receiver's sensitivity threshold during a test, a BER tester is used to measure the rate of errors in transmitted data. This threshold is critical for ensuring data integrity in communication systems.
Step-by-step explanation:
To determine the receiver sensitivity threshold during a receiver sensitivity test, the appropriate instrument to use is a BER tester (Bit Error Rate tester). The BER tester assesses the performance of a system by measuring the rate of errors that occur in the transmission of binary data. A variable optical attenuator is sometimes used alongside a BER tester to adjust the signal strength down to the sensitivity level to ascertain the threshold at which the receiver can no longer correctly interpret the signal.
The receiver sensitivity threshold is the minimum power level at which the receiver can detect the signal with a specified bit error rate, typically 10-9. Lower sensitivity thresholds indicate a better receiver performance, as the device can accurately process signals with weaker strength. This is crucial for maintaining the integrity of data transmission in various communication systems.