Abstract: Guide elements along paths and turns of a network emit guide signals for guiding vehicles along the paths and through the turns. Control elements, located at points in the network at which the locomotion of approaching vehicles may need to be controlled, emit control signals, such as "stop" and "start" signals. The signals are preferably various modulated and unmodulated sine waves having frequencies programmable by a system supervisor that sends itineraries to vehicles prescribing their respective travel routes, each itinerary containing at least a set of identifiers uniquely corresponding to the signals emitted along the paths and turns in a travel route. The order of the set indicates the order of paths and turns to be taken while travelling a route. A system interface, hosted by each vehicle, acquires itineraries pertaining to its host vehicle and provides path/turn information to a vehicle driver--a person or an apparatus.

Abstract: A fiber-optic transducer apparatus, and a related method of manufacturing it, for particular use in medical applications such as invasive blood pressure and body temperature measurement. The apparatus includes a catheter comprised of a sheath and an enclosed first set of optical fibers for transmitting a light beam to and from the remote end of the catheter, where a transducer modulates it in accordance with the variable to be measured, e.g., blood pressure. A photosensor located at the near end of the catheter measures the modulated intensity of the returned beam, to produce a corresponding measurement signal. The catheter is further comprised of a second set of optical fibers located within the sheath, for transmitting a reference light beam to and from the remote end of the catheter. A second photosensor measures the intensity of the returned reference light beam, to produce a correction signal indicative of variations in transmittance caused by bending of the catheter.

Abstract: A method and apparatus for measuring the oxygen saturation level and hematocrit of human blood in real time. A catheter having a notch in its tip is inserted into a blood vessel and guided to a desired location in the body of a patient. Bursts of light at each of three wavelengths are transmitted through the blood in the notch. The intensities of the bursts of light after transmission are utilized along with a set of molecular exinction coefficients and optical scattering coefficients to calculate the oxygen level and hermatocrit. The light is provided by a set of LEDs in a housing connected to the catheter and the intensity of the transmitted light is measured by a photocell in the same housing. Optical fibers transmit the light through the catheter between the housing and the notch. Characterization resistors in the housing are encoded with characteristics such as the wavelengths of the LEDs and the width of the notch.

Abstract: An output circuit for a digital physiological measuring instrument. The output circuit provides means for a digital signal indicative of a physiological parameter to operate on an excitation signal from a monitor to provide a response signal for driving the monitor to generate a visual display of that parameter. The excitation signal is scaled in a digital-to-analog converter, corrected for a zero offset of the digital signal, and then applied to the monitor. A dummy excitation signal is provided to enable the output circuit to drive a readout device having an analog input but not providing an excitation signal.

Abstract: A heartbeat rate measuring system for monitoring a patient's EKG signal and estimating heartbeat rate. The system includes an artifact detection apparatus for filtering the EKG signal to detect the occurrence of a heartbeat artifact, and for inhibiting the measuring heartbeat intervals whenever an artifact is detected. The system therefore estimates heartbeat rate based solely on measurements of time intervals between actual heartbeats.

Abstract: A transducer system that provides accurate measurements of a physical variable such as pressure for any one of a number of different transducers. Each transducer includes special calibration indicators for identifying any inaccuracies in its output signal, and monitoring and correcting circuitry is selectively attachable to any one of the transducers, to read the calibration indicators and apropriately adjust the transducer's output signal, thereby correcting for the identified inaccuracies.

Abstract: A heart rate monitoring apparatus and related method for detecting the successive beats of a heart and providing a reliable estimate of heartbeat rate. The apparatus measures the time intervals between the successive beats and averages a prescribed number of the most recently occurring measurements. The particular measurement that differs most from the computed average is adjusted to be equal to that average, and the adjusted set of measurements is then averaged. These latter steps of adjusting and averaging are repeated a prescribed number of times, and the last-computed average is displayed as an estimate of heartbeat rate. The entire procedure is repeated upon the occurrence of each successive heartbeat.

Abstract: A digital servo control system for a d.c. motor to achieve stepping motor precision and a wider speed control range than either a conventional d.c. motor or a stepping motor, as may be typically utilized in an IV syringe pump. Motor position and direction sensing, as well as motor advance signals at the desired motor rate, condition motor advance and retard logic which, in turn, effects a unique counter-controlled motor drive subsystem to cause the d.c. motor to move forward, reverse, coast or slow down over a 1,000 to 1 speed control range.

Abstract: An electronic method and apparatus for evaluation of the quality of drop detection in apparatus for parenteral administration of medical fluids, wherein the waveforms of electrical signals representing drop flow detection are evaluated for conformity with both prescribed amplitude and time duration characteristics. Separate counters record the total number of drop events evaluated and the portion of the total which are determined to be non-conforming, and the latter counter triggers alarms if a predetermined limit is exceeded within a prescribed number of total events.