Abstract: A readout circuit for determining the displacement of a magnet relative to a fixed reference point is disclosed. The relative displacement is determined by measuring the time interval required for a stress wave created in a magneto-strictive probe adjacent to the magnet to travel to the reference point. The readout circuit includes a counter means for counting at a predetermined rate. In order to determine the displacement of the magnet using the readout circuit, a pulse signal is generated in the probe causing a stress wave to be created in the probe at the location of the magnet. The counter means of the circuit is then activated in timed relation to the generation of the pulse signal. A means for detecting the arrival of the stress wave at the reference point and for stopping the counter means when the wave is detected is also provided in the readout circuit. By measuring the travel time for the stress wave with the readout circuit, the displacement of the magnet is determined.

Abstract: A medical electronic diagnostic device particularly suitable for determining and displaying segmental pulsatile flow of a patient. Means are provided for stabilization of a calibrated segmental volume time curve relative to a baseline, so as to eliminate the effect of patient movement during testing, as well as miscellaneous electrical noise. The disclosed device is capable, in addition to displaying a pulse volume curve, of measuring and recording the pulsatile component of the total blood flow.