Diversity reception system

摘要

To reduce fading in a diversity receiver, the signals received on two spaced-apart antennas are added together without phase shift while amplitude of the sum is above a certain threshold. When the signal falls below the threshold, the signal from a squelch detector causes the sum amplitude to be stored and then a 180 DEG time delay to be inserted between one of the antennas and the adding circuit, after which time, the new sum amplitude is compared with the stored signal amplitude. If the new signal has increased or remained the same, the 180 DEG phase shift remains in place but, if it has deteriorated, it is removed and the circuit reset.