Coherent jamming is one of the important trends in modern radar electronic war-fare. High-speed sampling of wideband radio frequency (RF) signals and high iso-lation of two receive-transmit antennas are key technologies for the realization of coherent jamming. However, these technologies present significant challenges to engineering application. In this paper, a novel repeater jamming based on inter-rupted sampling technique is presented. For a jammer with a receive-transmit time-sharing antenna, a radar signal is sampled with a low rate by the jammer. Then, a train of false targets will be achieved after the jamming signal feed the matched filter of a pulse compression radar. For the case of the linear frequency modulated (LFM) pulse compression radars, mathematic principles of the interrupted-sam- pling repeater jamming is developed, and then the efficiency of the jamming is de-scribed and stated as expressions of key parameters which are also beneficial to the jamming design for other coherent radars.