This thesis contains an investigation of the principles, structure, and methodology of a multiple bandwidth tree based channelization scheme for modulation and demodulation. The backbone of the process relies on the features of multi-rate signal processing with specific support from polyphase filter structures. The half-band filter in polyphase form is the core of this structure. It is this filter structure that is assembled into a branching tree and used to perform the main processing tasks which enables a multi-channel communications architecture with compact support. Application specific polyphase filter structures for up-sampling and down-sampling are explained, modeled, and simulated to show how they can be effectively employed in the construction of the tree based channelizer. A process has been modeled and simulated to demonstrate the method and results of the tree based channelizer for modulation and demodulation. From these results, conclusions are drawn about how a tree based modulation and demodulation scheme can provide an effective means for multi-channel channelization.