A miniature transmitter was designed to telemeter muscle potentials from dogs. The implanted transmitter is operated by a nickel-cadmium battery. In order to obtain information over long periods of time, the battery is recharged by induction from an external power source. By using the oscillator transistor in an inverted configuration, the transmitter's circuit serves to recharge the battery without the addition of extra components. The simplicity of the circuit makes the unit compact and minimizes the failure of components. A magnetic switch is used to actuate the circuit, thus eliminating complete drain and degeneration of the battery.
This is an investigation concerning the feasibility of establishing an undergraduate bio-medical engineering program and an interpretation of the present trends and demands for students completing this field of study. The paper is based upon a statistical study of the opinions of deans of colleges, deans of medical schools, directors of medical hospitals and research centers and directors of engineering corporations, government agencies and employment agencies. The answers to selected questions were tabulated and various comments were recorded. It was found that there is definitely a need for personnel in this field and consequently the necessity of establishing an undergraduate program.
This paper describes a new instrument with excellent low frequency response for recording arterial pulse wave forms. It uses a fluid filled chamber and a stiff diaphragm to which a set of semiconductor strain gages are cemented.
The Helmholtz reciprocity theorem for currents in an inhomogeneous conducting media is put into a useful form for the solution of problems such as arise in electrocardiography. Several examples are considered which lead to known results and which illustrate the application of the method.
In peripheral organs a logarithmic relationship between stimulus and response holds for a rather wide range of input magnitudes. This relationship is clearly demonstrated for Limulus between the frequency of discharge in the optic nerve, and the intensity of stimulating light. A simple relaxation oscillator is envisioned to model the generation of nerve impulses. The necessary transfer function of the charging circuit of the oscillator is computed so that the frequency of oscillation should be proportional to the logarithm of the magnitude of the input voltage. It is shown that the obtained transfer function can be realized by a tapered RC transmission line. The experimental verification of the derivation is given.
