Question: What is the primary purpose of the cable calibration step in Over The Air (OTA) antenna performance conformance testing for User Equipment (UE)/Mobile Station (MS)?
Option 1: To optimize the transmission power of the UE during TRP measurements
Option 2: To validate the frequency response of the network analyzer itself
Option 3: To quantify and compensate for the power loss introduced by the cable in TRP/TRS measurements
Option 4: To establish a baseline for the chamber's electromagnetic interference (EMI) levels
Explanation: The correct answer, Option 3, reflects the essence of cable calibration in OTA antenna performance testing. By measuring the transmission S-parameter of the cable and saving its power transfer values, testers can accurately account for and compensate for the signal loss induced by the cable. This ensures the precision of both Total Radiated Power (TRP) measurements (received power at the fixed measurement antenna) and Total Radiated Sensitivity (TRS) measurements (power radiated by the fixed antenna). This process is crucial for reliable and standardized testing outcomes, unaffected by variable cable losses.