| 摘要 |
A low electric energy consumption circuit to detect parameters associated to the patient's respiration, suitable for the realization of implantable devices, such as implantable and physiologic pacemakers, is designed to detect, at the same sample rate of the impedance in a part of the patient's body, the voltage variations V ( DELTA ZL) corresponding to said impedance with both negative and positive variations from the base line. According to a first scheme, these variations V' ( DELTA ZL) are subsequently processed by means that produce a clean VOUT signal, e.g. a squared one, which shows a transition every time that the difference between minimum value and maximum value and maximum value and minimum value of the input signal exceeds a fixed a preferably programmable value. According to a second scheme, said variations V' ( DELTA ZL) are processed by means producing a signal proportional to the variation speed of the body impedance and by means producing a signal Vm ( DELTA ZL) that is the mean value or the average of the values of the input signal and that is proportional to the patient's pulmonary ventilation (l/min). |
