device 20 is shown in fig1 the direct to digital oximeter 10 comprises a charge digitizing analog to digital converter 30 a microprocessor 40 a digital to analog converter led driver 50 and a flash eprom 60 in order to achieve sufficient accuracy the charge digitizing analog to digital converter 30 preferably converts the input analog signal to a digital signal of at least 20 bits in a preferred embodiment see fig2 the sensor 20 is attached to a blood carrying tissue sample such as the finger or ear lobe of a patient here the sensor 20 is shown to consist of three light emitting devices 70 80 and 100 and a single photodetector 90 but the sensor can include two or more light emitting devices of different wavelengths and an associated plurality of photodetectors furthermore although leds are commonly used in circuits of this type the light emitting devices can be laser diodes white light sources or other suitable devices to perform traditional pulse oximetry however the sensor 20 comprises a red led 70 and an infrared led 80 the led 39 s 70 and 80 are driven by digital signals from the microprocessor 40 these digital signals are converted to.