Diversity system

Abstract

An antenna diversity system for the mobile reception of VHF and UHF television signals in different frequency ranges that are separated by gaps by a mobile television receiver connected to a plurality of antennas through an antenna switch, wherein the output of the receiver includes a color decoder for producing color and luminance video signals. There is provided a separate frequency diversity control circuit connected to the receiver for testing the UHF and VHF signals received by the antennas and for switching the antennas to receive the best quality video and audio signals. The diversity circuit tests and reverses the antenna switch within the blanking gap of the horizontal synchronization lines of the TV signal. Memory circuits are coupled to the color decoder of the receiver for receiving at least one synchronization line of the video signal from the color decoder wherein either the complete video signal or corresponding color and luminance signals thereof are continuously read line by line. A storage circuit stores at least the signal of one line received immediately prior to the antenna reversing process. The last line or several line signals are then read out from the memory circuits after the antenna is switched through to a new antenna. A comparator simultaneously compares the video signals or signal components stored in the memory circuits with the new antenna signals or its components, and detects the level difference of the respective line signals from both antennas. A control pulse is generated responsive to the level difference for effecting an accelerated level detection, and switching the antenna to the previously acting antenna using the automatic gain control (AGC) of the television receiver.