Abstract: An automatic position managing system is applied to a communication system which includes a plurality of telephone sets coupled to a private branch exchange. The automatic position managing system uses a radio card which is carried by a user and has the functions of storing information related to the user and transmitting the stored information by a radio signal. A first part supplies data to the private branch exchange in response to the radio signal received from the radio card and a second part automatically detects a position of the user carrying the radio card based on the data received from the first part via the private branch exchange by associating the user with the telephone set to which the first part is coupled.

Abstract: A mechanical filter having as its major part at least one longitudinal vibration mode vibrator, includes a piezoelectric ceramic plate an electrode pair attached to top and bottom surfaces thereof. The piezoelectric ceramic plate is polarized in its thickness direction to form at least two polarized regions, the polarization directions being different from each other.

Abstract: A mechanical filter including at least two longitudinal mode vibrators, each of which is a piezoelectric ceramic member with constant modulus alloy members mounted separately on the top and bottom surfaces thereof. The two constant modulus alloy members have the same configuration, a frequency-temperature characteristic opposite to that of the piezoelectric ceramic member, and are aligned, at their individual centers, with the center of the piezoelectric ceramic member. The configurations of the two longitudinal mode vibrators can be predetermined to suppress higher order spurious vibration modes inside the mechanical filter itself.

Abstract: A mechanical filter having at least a pair of mechanical vibrators which are arrayed approximately in parallel with each other in regard to their longitudinal axes, and two couplers which are coupled to the pair of mechanical vibrators. According to the mechanical filter one of the pair of mechanical vibrators undergoes the vibration of the order of an odd number and the other one undergoes the vibration of the order of an even number in the same vibration mode, or both of them undergo the vibration of the order of an odd number or even number in the same vibration mode. Furthermore, these mechanical vibrators have such a mechanical size that they will vibrate at their required order of vibration and at their respective resonance frequencies, and the two couplers are so constructed that they will be differentially coupled to the pair of mechanical vibrators approximately at right angles therewith.

Abstract: A flexural electromechanical transducer composed of a constant-modulus alloy material and a piezoelectric ceramic material having a high electromechanical coupling coefficient. In the transducer, the piezoelectric ceramic material is polarized in one direction and a specified frequency signal is applied to the piezoelectric ceramic material in a direction parallel to the residual polarization direction of the piezoelectric material for obtaining a thickness-shear vibration. The thickness-shear vibration of the piezoelectric material in turn causes the flexural vibration of the transducer. The transducer achieves a high quality factor Q, a low capacitance ratio r, good spurious characteristics, and low impedance.

Abstract: An electromechanical filter having minimum attenuation deviation in the pass band frequency range. The filter includes a plurality of mechanical resonators arranged substantially parallel to each other in one plane and mechanical couplers of longitudinal resonance characteristics which are disposed substantially transverse to the plurality of resonators for coupling the resonators together. The couplers have lengths which are between the first and second, and second and third oscillation modes of the longitudinal resonance characteristics. By virtue of the above structure, the couplers can be formed in a single mechanical coupling wire.