Multiple antenna scanning diversity system circuitry

摘要

The circuitry is for a multiple antenna scanning diversity system for vehicles, with an antenna arrangement with a controllable switch unit (11). Different switch positions send different reception signals to a receiver which drives a diversity processor (1). If reception interference is present the switch changes to another switch position. The diversity processor (1) includes a hold input (4). The arrangement also includes a switch testing device (3) comprising a register (6), two timers (8, 9) and a logic circuit (7). The tester (3) constantly registers the time of switching of the switch unit (11) in the register (6). The logic circuit (7) is such that the switch (11) is prevented from switching in a hold period (tH) set by the second time element (9) by a stop signal at the hold input (4) when a predetermined number of switches is determined in the logic circuit (7) within a reference time (tref) set by the first time element (8). The hold period is selected to be longer than the reference time.