Abstract: The invention relates to apparatus for testing a pulsed light oximeter, such as a non-invasive oximeter which emits pulses of red and infrared light. A light sensor produces an electrical pulse signal representative of light flashes emitted by the oximeter, and a signal generator produces a plurality of absorbance signals representative of the optical absorbance of an anatomical part at the wavelength of each light flash. A signal selector responds to time interval, duration and amplitude features of the electrical pulse signal, or to electrical signals produced by the oximeter itself, and thereby selects one of the plurality of absorbance signals to produce a selected absorbance signal. The selected absorbance signal is converted to light and conveyed to the oximeter to simulate the effect of the anatomical part on the light flashes emitted by the oximeter.

Abstract: An apparatus for measuring the flow of a liquid through a conduit by observing the transit of an injected gas bubble through the conduit. A gas source, responsive to the pressure of the liquid in the conduit, supplies gas at a predetermined pressure to a gas injector. This allows the gas injectors to inject a predetermined volume of gas into the conduit, largely independent of the absolute pressure of the liquid. An image, produces a conduit image representative of the gas bubble and the liquid in the conduit, comprising a plurality of elements corresponding to a plurality of predetermined locations along the conduit. A timer responsive to the conduit image produces a plurality of transit times substantially equal to the times required for the gas bubble to transit between adjacent predetermined locations. A time analyzer and indicator are included for analyzing the plurality of transit times and indicating the flow of the liquid through the conduit.