The Scientist and Engineer's Guide to Digital Signal Processing

http://www.dspguide.com/pdfbook.htmFOUNDATIONSChapter1-TheBreadthandDepthofDSPTheRootsofDSPTelecommunicationsAudioProcessingEchoLocationImageProcessingChapter2-Statistics,ProbabilityandNoiseSignalandGraphTerminologyMeanandStandardDeviationSignalvs.UnderlyingProcessTheHistogram,PmfandPdf