Patent ID: 9575030
Date: 2017-02-21
CPC Classifications: G01N

Claim:
1. An apparatus for detecting a difference in oxygen content in a test medium relative to a reference medium, comprising: a computer comprising a digital signal processing system, which is configured to sample signals at a sample-frequency suitable to resolve data conveyed by a digital control circuit, the computer configured to send and receive digital signals so as to communicate with and operate circuitry comprising said apparatus, and wherein the computer is further configured to sample output signals at predetermined switch times so as to reduce the total number of samples that must be performed; an oxygen sensor comprising at least one Nernst cell and a pump cell, wherein the oxygen sensor is configured to electrically indicate the difference in oxygen content in the test medium relative to the reference medium; a pump control circuit configured to operate the pump cell according to signals received from the computer, the pump control circuit comprising a digital-to-analog converter in operative communication with the computer; a reference voltage circuit configured to determine an impedance of the oxygen sensor according to signals received from the computer; and a Nernst read circuit configured to amplify output signals from the oxygen sensor and transmit the signals digitally to the computer, wherein the signals received by the computer are compared with stored reference information to determine the oxygen content of the test medium.