Question: In the context of Base Station (BS) conformance testing for TDD (Time Division Duplex) mode, what type of signals are used to test in-band and out-of-band blocking characteristics of a receiver?
Option 1: For both in-band and out-of-band blocking, a CW (Continuous Wave) signal is utilized.
Option 2: In-band blocking is tested with a CW signal, while out-of-band blocking uses a narrow band CDMA signal with one code.
Option 3: In-band blocking is evaluated using a narrow band CDMA signal with one code, whereas out-of-band blocking is assessed with a CW signal.
Option 4: Both in-band and out-of-band blocking characteristics are tested solely with a wideband CDMA signal.
Explanation: This correct answer reflects the nuanced understanding of telecom testing standards. The use of a narrow band CDMA signal with one code for in-band blocking simulates interference from within the same frequency band, testing the receiver's ability to filter out nearby signals. Conversely, a CW (Continuous Wave) signal is used for out-of-band blocking to assess the receiver's resilience against single-frequency interferers outside its assigned channel, mimicking potential external interference sources. This distinction is crucial in evaluating a base station's receiver performance under various interference conditions in a TDD system.