Abstract: A radar system comprising a filter with a variable pass band to which radar video signals are fed, data storage means including a main store having a plurality of storage addresses into which data appertaining to the velocity of targets in a plurality of range bearing cells is fed one cell to each address and control signal producing means operative to set the frequency of the filter in dependence upon stored data so that for reception of video signals appertaining to any specified range/bearing cell the frequency of the filter is set in dependence upon the data stored in the address of the main store corresponding to that specified range/bearing cell which appertains to the velocity of any target detected in that range/bearing cell in immediately preceding scans.