Patent US 3,944,796

A conventional stereo tape recorder is used to record a series of reference pulses on each of the two channels or magnetic tape tracks followed in each instance by intermediate event pulses representative of behaviorial phenomena or units. The delay or time interval between reference pulses and event pulses is indicative of the particular behavior that has been observed. An astable or free running multivibrator for each channel provides the reference pulses, whereas a monostable or one-shot multivibrator, which is triggered by its companion astable multivibrator, provides the event pulses. A key-controlled resistance-capacitance circuit connected in the monostable circuitry functions to vary the delay or position of the event pulses with respect to the reference pulses. Individual keys, or combination of keys, are assigned codes representative of the various behaviors and subjects to be observed and recorded. The recorder at some later time is interfaced with an appropriately programmed computer, the computer then processing the tape signals on a time basis provided by the computer clock and converting such signals to binary values representative of the various time delays or time positions of the intermediate event pulses with respect to the reference pulses. The computer can perform various logical functions, such as ratioing, averaging and sorting, and then store the results in its memory for appropriate analysis, such as determining behavior patterns of the subjects that have been previously observed.