The TOPS Electronic Warfare channelizer program is an effort being conducted under the DARPA sponsored Transition of Optical Processing into Systems (TOPS) initiative. The objective is a high probability-of-intercept radar receiver for signals in dense environments. Channelization is the preferred receiver approach in interfering signal environments because it instantly sorts time coincident pulse signals. Channelization is performed optically, using acousto-optical techniques, since optics offers size, weight, power and cost advantages. This program is a three year channelizer development effort. Once developed, the receiver will be tested integrated with an existing electronic warfare system. The paper will review the program background. The electronic, mechanical and optical requirements will be addressed. The critical technical issues impacting this program will be analyzed.