1. A training device for selectively monitoring one or more of a plurality of physiological signals produced by a human being and for displaying computed measures of such signals including: (a) a plurality of replaceable, selectable and interchangeable transducer means adapted to be singly and plurally utilized for conversion of said plurality of physiological signals into a corresponding plurality of equivalent electrical signals; (b) a plurality of corresponding signal conditioning means for said equivalent electrical signals including adjustable electrical amplification means, filtering means and conversion means adapted to convert said plurality of said conditioned equivalent electrical signals into a corresponding plurality of equivalent equipotential pulse trains, each of whose instantaneous frequencies is proportional to each of said corresponding plurality of said conditioned equivalent electrical signals; (c) a plurality of display means operative for presentation of said plurality of equivalent equipotential pulse trains as computed measures of said physiological signals; (d) terminal means for control of said training device by the said human being; (e) a plurality of relatively independent computer means cooperating in selective combinations and at least one combination of which is adapted to calculate said computed measures of said corresponding plurality of equivalent equipotential pulse trains, and another combination of which is adapted to control at least one of said plurality of display means; (f) supervising computer means adapted to control, select and/or coordinate said plurality of said relatively independent computer means; and (g) communication bus means adapted to transmit information between said plurality of relatively independent computer means and said supervising computer means.