Pressure transducers

Claim 1

A PRESSURE TRANSDUCER PROVIDING FREQUENCY MODULATED SIGNALS IN DEPENDANCE UPON THE PRESSURES OF A FLUID MEDIUM AND SUBSTANTIALLY INDEPENDENT OF THE TEMPERATURE VARIATIONS OF SAID MEDIUM, SAID TRANSDUCER COMPRISING: A VIBRATORY HOLLOW MEMBER OF MAGNETIC MATERIAL, SAID HOLLOW MEMBER DEFINING A CHAMBER; A CASING ENCLOSING SAID HOLLOW MEMBER; A LIQUID FILLING THE SPACE BETWEEN THE OUTER WALLS OF SAID HOLLOW MEMBER AND SAID CASING, SAID LIQUID HAVING A PREDETERMINED DENSITY-VERSUS-TEMPERATURE CHARACTERISTIC; A FLUID IN SAID CHAMBER, SAID FLUID BEING UNDER A PREDETEMINED PRESSURE; PRSSURE EXCHANGING MEANS TERMINATING SAID CASING FOR COMMUNICATING THE PRESSURES OF SAID FLUID MEDIUM TO SAID LIQUID, SAID PRESSURE EXCHANGING MEANS INCLUDING A RIGID MOVABLE WALL; A COMPENSATING MEMBER MOUNTED BETWEEN THE OUTER WALL OF SAID HOLLOW MEMBER AND THE INNER WALL OF SAID CASING; LINKING MEANS COUPLING SAID WALL WITH SAID COMPENSATING MEMBER, SAID COMPENSATING MEMBER BEING DISPLACEABLE RELATIVE TO ONE END OF SAID HOLLOW MEMBER IN RESPONSE TO DISPLACEMENTS BY SAID MOVABLE WALL; FIRST MEANS HOUSED IN SAID CHAMBER FOR IMPARTING VIBRATIONS TO SAID HOLLOW MEMBER; AND SECOND MEANS INSIDE SAID CHAMBER RESPONSIVE TO THE VIBRATIONS OF SAID HOLLOW MEMBER FORP ROVIDING AN OS CILLATORY ELECTRIC SIGNAL, THE FREQUENCY OF SAID SIGNAL VARYING AS A FUNCTION OF VARIATIONS IN THE PRESSURES OF SAID FLUID MEDIUM.