Abstract: A semiconductor transducer comprising an improved strain-yielding body yielding a strain in response to the impartation of a force or displacement, and a semiconductor strain gauge bonded to the strain-yielding body. The improved strain-yielding body is made of an iron-nickel-cobalt alloy containing 28.2 to 31.0% by weight of nickel and 15.0 to 19.5% by weight of cobalt. This iron-nickel-cobalt alloy is initially heated up to a temperature above 600.degree. C. for the purpose of standard heat treatment for removing its internal strain. After the standard heat treatment, the iron-nickel-cobalt alloy is subjected to cold working at a working rate of more than and including 60%, and is then subjected to heat treatment at a temperature between 350.degree. C. and 600.degree. C. The heat-treated iron-nickel-cobalt alloy is shaped into the predetermined form of the strain-yielding body.

Abstract: In an ultrasonic data communication system, each datum is represented by a specific ultrasonic wave signal composed of plural frequency components arranged according to a specific one of predetermined frequency permutations so that the data transmission time can be considerably reduced without the influence of reverberation.

Abstract: A signal to be transferred comprises a plurality of patterns each including a time region containing a plurality of frequency signals and a time region containing no frequency signal. When a signal to be transmitted is given in the form of numeric information, this signal is automatically patterned by a transmitter unit to provide a period containing predetermined frequency signals and a period containing no frequency signal. A receiver unit reproduces the sequentially transmitted frequency signals on the basis of the reception of the first transmitted frequency signal.

Abstract: A data transmission system is disclosed in which the information to be transmitted comprises a plurality of unit information pieces each of which in turn is indicated by a numerical code of a binary number or a binary-coded decimal number having a predetermined number of bits.