In the case of a transducer for the simultaneous measurement of different physiological quantities, with a measuring head which contains a transducer for measuring a first physiological quantity and a transducer having electrodes connectable with signal processing electronics for measuring a bioelectric...http://www.google.ca/patents/US4538617?utm_source=gb-gplus-sharePatent US4538617 - Transducer for the simultaneous measurement of different physiological quantities
