A Variable Criterion Circuit for Biofeedback Training

A circuit is described which provides feedback from one of many varying physiological parameters by comparing the instantaneous present value to an integrated version of the same parameter. A success or failure signal is generated when the instantaneous value falls below or exceeds the integrated level. Furthermore, the integrated level is continually updated, so that eventually (depending on the selected time constant) the integrated level will equal the instantaneous level if it remains stable; thus a trainee cannot succeed or fail for a long period of time. A design for a continuous analog display of the values on an oscilloscope is also described.