A new framework on the representation of signal processing that considers multi-domain information flow of the signal is proposed. Elementary information processing and their diagrams are identified to analyze the components of an algorithm, which is to be translated to the diagram. Intra- and extra-domain relationships are represented as graphs that connect the corresponding domains by suitable mappings or transforms and corresponding emissions or absorption of information. Various examples: convolution, wavelet filtering, projection imaging and coding in noisy channel; are presented to show the ubiquity and to illustrate the usability of the proposed framework.