FILTERANORDNING INGAENDE I EN PULSDOPPLERRADAR

摘要

A receiver for pulse Doppler radar equipment using p.r.f. staggering includes a digital filter arrangement for reducing clutter within a lower speed range (Sg) and a higher speed range (Sm). The arrangement includes a first digital filter (DF1) having a pass band/ stop band characteristic such that the lower clutter is rejected by the lowest stop band of the first filter but the desired target echo signal(s) falls within a pass band, a circuit (HK) connected to an output of the first filter for calculating a dominating frequency component of the higher clutter (Sm) and carrying out a downwards transfer in frequency of the clutter signals recovered from the first filter so that the mean frequency of the higher clutter assumes a value within the first stop band of a second digital filter (DF2), substantially coinciding with the first stop band of the first filter in order to suppress the higher clutter.