TOESTEL VOOR HET VERSCHAFFEN VAN EEN HOORBARE WEERGAVE VAN ELEKTRO-FYSIOLOGISCHE SIGNALEN.

摘要

A medical diagnostic apparatus for producing an audible indication of the nature of electric signals produced in the human body by the action of the heart. An audio frequency carrier wave is modulated both in frequency and in amplitude in accordance with the aforesaid applied electric signals. The level of the fundamental tone normally remains below the limit of audibility. This limit is exceeded only when an electric heartbeat signal occurs.