A high-speed 4-channel ADC is used when the customer has a diversity receiver. Diversity receivers are used when there are 2 antennas on a cell phone tower that are one-quarter wavelength apart. One antenna will get a stronger signal than the other one. The customer can phase shift the received signals and add them. A quad ADC like the one shown here can accept the demodulated I & Q signals from the 2 antennas.