Abstract: The amplitude of a pulse wave that appears in a form superimposed upon cuff pressure is detected every beat of a heartbeat in synchronism with the beat not only in the course of depressurization but also in the course of pressurization. The maximum value Amaxi of the pulse-wave amplitude in the course of pressurization is multiplied by a prescribed coefficient to decide a threshold value TH. The threshold value TH is calculated as a value equivalent to a pulse-wave amplitude corresponding to systolic pressure that would be determined in the course of depressurization. After the cuff is pressurized to the target pressure, a transition is made to the depressurizing process. It is judged that cuff pressurization is inadequate if the initial pulse-wave amplitude in the course of depressurization is greater than the threshold value TH. Thus, whether or not cuff pressurization is inadequate can be judged appropriately at all times without any influence due to personal differences or physical condition.

Abstract: An angle of rotation detector has a drive unit which supplies 90 degree phase shifted signals to a pair of stator coils and measures an analog output from a rotor coil in a resolver. A calculating device calculates the rotational angle of the resolver using the output of an analog to digital converter receiving the analog output of the rotor. In one embodiment, the calculating device performs a Fourier transform to compute the phase of a fixed frequency component contained in the output of the rotor coil. In another embodiment, the drive unit supplies signals wherein f(T/2+t)=-f(t) and the calculating device performs a Fourier transform using data from successive half periods of the drive waveform. In another embodiment, the output of the rotor is sampled at 1/4 period of an excitation signal from the drive unit and the calculating device determines the phase difference between the excitation signal and the rotor output.

Abstract: An electric sphygmomanometer has a cuff, a pulse wave detecting photoelectric sensor including a light-emitting element and a light-receiving element which are disposed on the cuff, as well as a memory for storing measured data. Either a measuring mode or a transmitting mode may be selected, and the light-emitting and -receiving elements of the pulse wave detecting photoelectric sensor may be used as light-emitting and -receiving elements for transmission of measured data in the transmitting mode. As a result of this arrangement, it is possible to transmit measured data stored in the memory to an external data processor readily and inexpensively without the need for special hardware.