What is predictive diversity? Is it different from true diversity or Marcad diversity?
Predictive Diversity is two antennas connected to a single receiver section. A microprocessor monitors the slope of the RF level to predict when a dropout will occur at an individual antenna. The microprocessor switches antennas before the dropout occurs.
MARCAD is explained at: http://www.shure.com/publications/selection_and_operation_of_wireless_microphone_systems_english.pdf
Both MARCAD and Predictive Diversity are types of True Diversity systems. True Diversity is defined at the above link.