If Alias Protect is True, the ESA uses the 10MHz span setting, which is alias protected, regardless of the span set using 89600 interface (see ESA Setup - Span). The ESA captures and corrects the signal IQ pairs in the 10MHz span and transfers the alias protected data to 89600, which then decimates and filters the data using analysis span set in the 89600 interface.

If Alias Protect is False (default), the ESA uses its lower cardinal BW's, which are implemented using sub-sampling, to achieve the required capture lengths for measurements, but these lower BW's are not alias protected. To achieve good measurement results in this case, you must band limit the signal to the measurement span.

Alias Protect and Digital Demodulation The disadvantage of setting Alias Protect to True is that the capture length is limited to that of the 10MHz span setting (approximately 8.29 milliseconds minus filtering settling). This is enough data to do useful Digital Demod measurements on higher data rate formats like WCDMA, cdmaOne, cdma2000, GSM, and EDGE formats, but not enough to do Digital Demod measurements on lower data rate formats like NADC, PDC and TETRA.

Note If the hardware setup cannot acquire enough time samples to complete the requested Digital Demodulation measurement, the analyzer displays an error message: Demod: Not enough data.

When Alias Protect is True, the Code Domain Power (CDP) measurements are clipped to 11 Slots (0.733Frame) for WCDMA and 5PCGs (0.3125 Frame) for cdma2000.

Target Platforms: Windows 11 Professional or Enterprise; Windows 10 Professional, Enterprise, or Education (64-bit)

Reference