This discussion explains time waveform analysis in authenticity examinations of the serial time code information and describes the specific data placed on the logging systems commonly used by police departments and other sources of investigative tapes. As it is inherently difficult to modify a logging tape, an authenticity examiner often is trying to determine if there has been an alteration, or in the case of a broken tape, whether any information has been lost. Time waveform displays provide a visual pattern of the pulse data of the codes. These then can be deciphered into binary digits which directly represent time of day and other information. 5 figures, 1 table, and 5 references