Pulse oximetry testing
First Claim
1. An apparatus for testing a pulse oximeter having means for optically sensing SpO2 values of living tissue, electrical drive means for electrically activating the optically sensing means, and electrical signal processing means responsive to the optically sensing means for producing an oximeter signal corresponding to the SpO2 value being sensed, said testing apparatus comprising:
- first testing means bypassing the optically sensing means and responsive to the electrical drive means for generating selected first electrical test signals respectively representative of selected SpO2 values in living tissue and for transmitting said first signals to the electrical signal processing means to test the ability of the signal processing means to process said representative SpO2 values and produce oximeter signals corresponding to the selected SpO2 values represented by the test signals generated, andsecond testing means for generating second electrical test signals, for transmitting the same to the optically sensing means, for receiving response signals from the optically sensing means in response to transmission of the second test signals, and for providing an indication of said response signals thereby to test the optically sensing means separately from said testing by the first testing means.
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Abstract
A method and apparatus for testing a pulse oximeter which is based on the concept of an electrical interface between the testing instrument and the oximeter rather than an optical interface. The pulse oximeter signal processor is tested separately from the probe, and still further, the optical elements, that is, the LEDs and the photodiode, of the probe are tested separately from the probe cable. With the probe disconnected from the oximeter, a modulated electrical test signal representative of SpO2 values and other parameters is generated in response to an electrical signal from the oximeter, and the test signal is applied to the oximeter signal processor, whereby the display of the oximeter shows a value of SpO2 which is compared with the SpO2 value represented by the test signal. Independently, the probe including the probe cable, the LEDs and the photodiode are respectively and separately subjected to continuity and optical sensitivity tests. Each of the main components of the oximeter is thereby separately analyzed, and the source of a defect is isolated.
20 Citations
62 Claims
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1. An apparatus for testing a pulse oximeter having means for optically sensing SpO2 values of living tissue, electrical drive means for electrically activating the optically sensing means, and electrical signal processing means responsive to the optically sensing means for producing an oximeter signal corresponding to the SpO2 value being sensed, said testing apparatus comprising:
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first testing means bypassing the optically sensing means and responsive to the electrical drive means for generating selected first electrical test signals respectively representative of selected SpO2 values in living tissue and for transmitting said first signals to the electrical signal processing means to test the ability of the signal processing means to process said representative SpO2 values and produce oximeter signals corresponding to the selected SpO2 values represented by the test signals generated, and second testing means for generating second electrical test signals, for transmitting the same to the optically sensing means, for receiving response signals from the optically sensing means in response to transmission of the second test signals, and for providing an indication of said response signals thereby to test the optically sensing means separately from said testing by the first testing means. - View Dependent Claims (2, 31, 32, 33, 34, 35)
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3. An apparatus for testing a pulse oximeter capable of sensing the SpO2 in living tissue and including a probe including LEDs and a photodiode;
- and an electronic unit including an LED driver providing output signals for activating the LEDs, an electronic signal processor for receiving and processing input signals from the photodiode in response to activation of the LEDs, and a display for showing the SpO2 values represented by the input signals, said probe releasably interconnecting the LED driver and the LEDs and the photodiode and the signal processor, comprising;
means operable with the probe disconnected from the LED driver and the signal processor for providing electrical test signals in response to output signals from the LED driver; means for modulating said electrical test signals so as to provide modulated electrical test signals representative of selected SpO2 values corresponding to those in living tissue; and means for transmitting said modulated electrical test signals to the signal processor in place of said input signals to cause the signal processor to process the test signals as if they were said input signals whereby SpO2 values shown on the display can be compared with a range of selected SpO2 values corresponding to the modulated electrical test signals thereby to test said electronic unit over its normal operating range. - View Dependent Claims (4, 5, 36)
- and an electronic unit including an LED driver providing output signals for activating the LEDs, an electronic signal processor for receiving and processing input signals from the photodiode in response to activation of the LEDs, and a display for showing the SpO2 values represented by the input signals, said probe releasably interconnecting the LED driver and the LEDs and the photodiode and the signal processor, comprising;
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6. An apparatus for testing the probe of a pulse oximeter having an electronic unit including an LED driver and an electronic signal processor;
- said probe including red and IR LEDs, a photodiode, and a probe cable, said probe cable being releasably connected to the driver and the signal processor when the probe is being used to sense the SpO2 of living tissue and to feed a signal representative of the same to the signal processor, comprising;
means for supplying current to the LEDs and the photodiode while the probe is disconnected from the driver and the signal processor to provide electrical continuity outputs from the LEDs and the photodiode; means for driving the LEDs while the probe is disconnected from the driver and the signal processor so as to activate the photodiode and provide electrical sensitivity outputs from the photodiode; and means for sensing said outputs thereby to indicate the sensitivity and the continuity of the probe.
- said probe including red and IR LEDs, a photodiode, and a probe cable, said probe cable being releasably connected to the driver and the signal processor when the probe is being used to sense the SpO2 of living tissue and to feed a signal representative of the same to the signal processor, comprising;
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7. An apparatus for testing a pulse oximeter probe which includes optical sensing means providing an LED circuit including red and IR LEDs and a photodiode circuit including a photodiode, there being an interactive red LED-photodiode combination and an interactive IR LED-photodiode combination, said LED circuit, said photodiode circuit, said interactive red LED-photodiode combination, and said interactive IR LED-photodiode combination constituting first, second, third, and fourth parts, respectively, of the optical sensing means capable of being tested for continuity and sensitivity, comprising:
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current supply means simultaneously connectable to the LED and photodiode circuits for causing testing current to flow in at least one of said circuits and for producing test output signals representative of the test results on at least one of said parts of the optical sensing means; and means for receiving the test output signals and being responsive to the magnitude thereof to produce an indication of the results of said test to a user of the apparatus. - View Dependent Claims (8, 9, 10)
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11. An apparatus for testing the continuity of a pulse oximeter probe which provides an LED circuit and a photodiode circuit, said apparatus comprising:
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means for activating each of said circuits so as to produce an electrical test output in each circuit representative of whether the circuit is open, continuous or shorted; means for separating the test outputs representing the LED circuit from the test outputs representing the photodiode circuit; and means for analyzing each of said outputs to determine whether or not the LED circuit or the photodiode circuit is open, continuous or shorted. - View Dependent Claims (12, 13, 14)
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15. An apparatus for testing the sensitivity of a pulse oximeter probe which provides red and infrared LEDs an a photodiode adapted to be alternately activated by said LEDs, said apparatus comprising:
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means for electrically alternately activating the LEDs so as to produce electrical red and IR sensitivity test output signals from the photodiode; means for producing red sensitivity/IR sensitivity ratio signals from said red and IR test output signals; and means for indicating each of said red sensitivity, IR sensitivity and red sensitivity/IR sensitivity ratio signals to determine the sensitivity of the optical sensing means. - View Dependent Claims (16, 17, 44)
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18. A method for testing a pulse oximeter having means for optically sensing SpO2 values in living tissue, means for electrically activating the optically sensing means, and electrical means responsive to the optically sensing means for indicating the SpO2 value in tissue being sensed, said method comprising the steps of:
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generating first test signals representative of SpO2 values in living tissue in response to the electrically activating means and independently of the optically sensing means, transmitting the first test signals to the electrical responsive means independently of the optically sensing means to test the ability of the oximeter to indicate said representative SpO2 values, generating a second test signal independently of the electrically activating means for testing the optically sensing means, transmitting the second test signal to the optically sensing means independently of the electrically activating means, and receiving an output from the optically sensing means indicative of the responses of the optically sensing means to the second test signal, thereby to test the operability of the optically sensing means. - View Dependent Claims (19, 20, 45, 46)
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21. A method for testing a pulse oximeter over a range of values of SpO2 expected to exist in living tissue said oximeter having a probe including LEDs and a photodiode;
- and an electronic unit including an LED driver providing an output signal for activating the LEDs, an electronic signal processor for receiving and processing input signals from the photodiode representative of SpO2 values in living tissue in response to activation of the LEDs, and a display for showing the SpO2 values represented by the input signals, said probe releasably interconnecting the LED driver and the LEDs and the photodiode and the signal processor, comprising the steps of;
disconnecting the probe from the driver and signal processor; generating an electrical test signal in response to the output signal from the LED driver; modulating said electrical test signal so as to provide a modulated electrical test signals representative of selected SpO2 values in living tissue; transmitting said modulated electrical test signals to the signal processor in place of said input signals to cause the signal processor to process the test signals as if they were said input signals thereby to test said electronic unit and, displaying the selected SpO2 values so that a comparison can be made with the SpO2 values displayed by the oximeter display to determine the accuracy of the oximeter over a range of SpO2 values. - View Dependent Claims (22, 23)
- and an electronic unit including an LED driver providing an output signal for activating the LEDs, an electronic signal processor for receiving and processing input signals from the photodiode representative of SpO2 values in living tissue in response to activation of the LEDs, and a display for showing the SpO2 values represented by the input signals, said probe releasably interconnecting the LED driver and the LEDs and the photodiode and the signal processor, comprising the steps of;
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24. A method for testing a pulse oximeter probe which includes optical sensing means providing an LED circuit including red and IR LEDs and a photodiode circuit including a photodiode, there being an interactive red LED-photodiode combination and an interactive IR LED-photodiode combination, said LED circuit, said photodiode circuit, said interactive red LED-photodiode combination, and said interactive IR LED-photodiode combination constituting first, second, third, and fourth parts, respectively, of the optical sensing means one or more of which is capable of being tested for the parameters of continuity and sensitivity, comprising the steps of:
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electrically activating said circuits so as to produce electrical test output signals which are representative of at least one of the parameters to-be-tested; and sensing the test output signals and displaying an indication of whether one or more of said parts meet the standards established for said at least one of the parameters to-be-tested. - View Dependent Claims (25, 26, 27, 28, 48)
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29. A method for testing the continuity of a pulse oximeter probe which provides an LED circuit and a photodiode circuit, comprising the steps of:
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activating each of said circuits so as to produce an electrical test output in each circuit representative of whether the circuit is open, continuous or shorted; separating the test outputs representing the LED circuit from the test outputs representing the photodiode circuit; and analyzing each of said outputs to determine whether or not the LED circuit or the photodiode circuit is open, continuous or shorted. - View Dependent Claims (30)
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37. An apparatus for testing the continuity of a pulse oximeter probe which provides LED and photodiode circuits connected to LED and photodiode terminals of a probe connector, said apparatus comprising:
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means simultaneously connectable to the LED and photodiode terminals of the probe connector for activating each of said circuits so as to produce an electrical test output in each circuit representative of whether the circuit is open, continuous or shorted; and means responsive to said test outputs for displaying indicia representing whether said LED and photodiode circuits are open, continuous or shorted. - View Dependent Claims (38, 39, 40, 41, 42)
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43. An apparatus for testing the continuity of a pulse oximeter probe that has an LED circuit and a photodiode circuit, comprising
means for supplying testing current to each of the LED and photodiode circuits to produce responses including separate analog LED and photodiode continuity voltages, means for combining said voltages into a single voltage signal with alternating LED and photodiode pulses, means for converting the single voltage signal into a series of discrete digital voltage pulses representative of the alternating LED and photodiode pulses, means for sampling the digital voltage pulses, display means, and means for activating the display means with the signal samples to indicate whether the LED and photodiode circuits are open, continuous, or shorted.
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47. A method for testing a pulse oximeter probe which includes optical sensing means providing an LED circuit including red and IR LEDs and a photodiode circuit including a photodiode, there being an interactive red LED-photodiode combination and an interactive IR LED-photodiode combination said LED circuit, said photodiode circuit, said interactive red LED-photodiode combination, and said interactive IR LED-photodiode combination constituting first, second, third, and fourth parts, respectively, of the optical sensing means to be subjected to such testing including the parameters of continuity and sensitivity, comprising the steps of:
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electrically activating said circuits so as to produce electrical test output signals which are representative of the parameters to-be-tested of said parts; electrically separating the test output signals so that there is a test output signal representative of continuity for each of said first and second parts and a test output signal representative of the sensitivity for each of said third and fourth parts; and analyzing each of said output signals to determine whether or not said parts meet the standards established for said parameters.
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49. A method for testing the continuity of a pulse oximeter probe that includes an LED circuit and a photodiode circuit, comprising the steps of:
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simultaneously connecting electrical activating means to both of the LED and photodiode circuits, electrically activating each of said circuits with test signals thereby to produce an electrical test output in each circuit representative of whether the circuit is open, continuous or shorted; and processing the test outputs to provide a visual indication of whether or not each circuit is open, continuous or shorted. - View Dependent Claims (50, 51, 52)
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53. A method for testing the continuity of a pulse oximeter probe that has an LED circuit and a photodiode circuit, comprising the steps of:
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supplying current to both the LED and photodiode circuits to produce responses including separate LED and photodiode continuity voltages;
sensing said responses and combining them into a single voltage signal with alternating LED and photodiode pulses;converting the single voltage signal into a series of discrete voltage pulses representative of the alternating LED and photodiode pulses; and using the discrete voltage pulses to display indications of whether the LED and photodiode circuits are open, continuous or shorted. .Iadd.
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56. circuits. .Iaddend..Iadd.67. An apparatus for testing the probe of a pulse oximeter, said probe including an LED, a photodiode, and a probe connector with LED and photodiode terminals respectively connected to the LED and photodiode, the testing apparatus comprising:
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a tester connector having LED and photodiode terminals capable of connecting to LED and photodiode terminals of the probe connector; a signal source that generates probe testing signals and that is connected to predetermined terminals of the tester connector for applying testing signals on the said predetermined terminals so that the testing signals will be applied to the probe when the tester connector is connected to the probe connector; a signal sensor that is connected to certain terminals of the tester connector, that is responsive to outputs thereon resulting from application of the probe testing signals to the probe, and that generates output signals representative of the outputs from the probe; and a display connected to the signal sensor for displaying an indication of said output signals, thereby to test the operability of the probe.
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57. Iaddend..Iadd.68. The apparatus of claim 67, the probe having LED and photodiode circuits respectively including the LED and the photodiode,
wherein the signal source generates probe continuity testing signals at the LED and photodiode terminals of the tester connector; -
wherein the signal sensor is connected to the LED and photodiode terminals of the tester connector, is responsive to continuity outputs on said LED and photodiode terminals resulting from the continuity testing signals, and generates continuity output signals representative of the continuity of the LED and photodiode circuits; and wherein the display shows an indication of the continuity of the LED and photodiode circuits. .Iaddend..Iadd.69. The apparatus of claim 67, wherein the signal source generates probe sensitivity testing signals at the LED terminals of the tester connector; wherein the signal sensor is connected to the photodiode terminals of the tester connector, is responsive to sensitivity outputs on said photodiode terminals resulting from the sensitivity testing signals, and generates sensitivity output signals representative of the sensitivity of the probe; and wherein the display shows an indication of the sensitivity of the probe. .Iaddend..Iadd.70. The apparatus of claim 69, the probe having red and IR LEDs, wherein the probe sensitivity signals generated by the signal source are high and low current signals for the red LED and high and low current signals for the IR LED, thereby to enable high and low red outputs and high and low IR outputs to be generated by the photodiode when the tester connector is connected to the probe connector; wherein the signal sensor is responsive to the high and low red outputs and generates red difference signals representing the difference between said high and low red outputs; wherein the signal sensor is responsive to the high and low IR outputs and generates IR difference signals representing the difference between said high and low IR outputs; and wherein the display is responsive to the red and IR difference signals and displays an indication thereof to indicate the sensitivity of the red and - View Dependent Claims (54, 55, 60)
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58. IR LEDs. .Iaddend..Iadd.71. A method for testing the continuity of a pulse oximeter probe that includes an LED circuit and a photodiode circuit, said method involving the use of a tester having a tester connector providing terminals connected to an electrically actuating source and a sensor in the tester, and a probe connector providing terminals connected to said circuits, comprising the steps of:
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connecting the tester connector to the probe connector and thereby simultaneously connecting the electrically activating source and the sensor to the LED and photodiode circuits, electrically activating each of said circuits with said source, sensing each circuit with said sensor for outputs in response to said electrical activation, producing indications of outputs that are sensed, and determining the continuity of the circuits from said indications. .Iaddend..Iadd.72. A method for testing the sensitivity of a pulse oximeter probe that has red and IR LED circuits and a photodiode circuit including a photodiode, said method involving the use of a tester having a tester connector providing terminals connected to an electrically actuating source and a sensor in the tester, and a probe connector providing terminals connected to said circuits, comprising the steps of; connecting the tester connector to the probe connector and thereby simultaneously connecting the electrically activating source and the sensor to the LED and photodiode circuits, electrically activating the LED circuits with said source, sensing the photodiode circuit with the sensor for outputs in response to said electrical activation, producing indications of outputs that are sensed, and determining the sensitivity of the photodiode from said indications. .Iaddend..Iadd.73. A pulse oximeter testing apparatus for testing a pulse oximeter having an optical sensor that senses SpO2 values of living tissue, an electrical driver that produces an electrical signal that activates the optical sensor, and a signal processor responsive to the optical sensor that produces an oximeter signal corresponding to the SpO2 value being sensed, said testing apparatus comprising; a current sensor that is responsive to the electrical signal from the electrical driver in the oximeter and produces simulated red and IR signals; an electronic memory storing SpO2 waveforms that simulate SpO2 waveforms in living tissue like those produced by the optical sensor in the normal operation of the oximeter; a modulator responsive to the simulated red and IR signals from the current sensor, modulating the simulated red and IR signals with selected simulated SpO2 waveforms from the memory, and generating modulated test signals respectively representative of the selected SpO2 waveforms in living tissue; and a tester driver responsive to the modulated test signals from the modulator, that produces electrical test signals representative of the selected SpO2 waveforms, and that transmits the test signals to the signal generator in the oximeter to test the ability of the signal processor to process said representative SpO2 waveforms and produce oximeter signals corresponding to the selected simulated SpO2 waveforms. .Iaddend..Iadd.74. The combination of a pulse oximeter and a testing apparatus, the oximeter having a signal processor, a display and a probe, the probe normally receiving signals from the oximeter and delivering modulated human signals to the signal processor resulting from a human finger or other body part placed in the probe, wherein the testing apparatus is connected to the oximeter in place of the probe; wherein the tester receives the signals from the oximeter that would normally be delivered to the probe; wherein the testing apparatus includes an electronic memory containing a database of waveforms corresponding to those produced by human fingers or other body parts when placed in the probe of an oximeter; wherein the testing apparatus also includes a modulator that modulates the signals received by the testing apparatus with selected waveforms from the electronic memory thereby generating modulated testing signals that simulate the modulated human signals resulting from a human finger or other body part placed in the probe when the oximeter is in its normal use; wherein the testing apparatus delivers the modulated testing signals to the signal processor; wherein the modulating testing signals are processed by the signal processor as if the modulating testing signals were the modulated human signals thereby producing processed signals; and wherein the processed signals are displayed on the display whereby comparisons can be made with known values. .Iaddend..Iadd.75. An apparatus for testing a pulse oximeter having an optical sensor that senses SpO2 values of living tissue, an LED driver, a signal processor responsive to the optical sensor that produces an oximeter signal corresponding to the SpO2 value being sensed and a display, said testing apparatus comprising; first means for testing the LED driver and the signal processor of the oximeter separately from the optical sensor of the oximeter, the display in the oximeter displaying the results of the first testing means; second means for testing the optical sensor of the oximeter separately from the LED driver and the signal processor of the oximeter; and means for displaying the results of the second testing means. .Iaddend..Iadd.76. An apparatus for testing a pulse oximeter having an optical sensor that senses SpO2 values of living tissue, a signal processor responsive to the optical sensor that produces an oximeter signal corresponding to the SpO2 value being sensed, and a display that displays the said SpO2 values sensed, the testing apparatus comprising; means for testing the signal processor of the oximeter with testing SpO2 values independently of the optical sensor; and means for enabling a comparison of the testing SpO2 values with the
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59. SpO2 values displayed on the oximeter display. .Iaddend..Iadd.77. An oximeter probe tester for an oximeter probe having LED and photodiode circuits, comprising:
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means for electrically activating the LED circuit and the photodiode circuit of the oximeter probe so as to produce electrical test output signals in the circuits that are representative of the continuity of the circuits, means for sensing whether or not the test output signals are present in the circuits, and means for displaying an indication of the test output signals sensed. .Iaddend..Iadd.78. An oximeter probe tester for an oximeter probe having a LED circuit including LEDs and a photodiode circuit including a photodiode, comprising; means for electrically activating the LEDs of the oximeter probe so as to produce electrical test output signals in the photodiode that are representative of the sensitivity of the photodiode, means for sensing the test output signals, and means for displaying an indication of the test output signals sensed. .Iaddend..Iadd.79. An oximeter probe tester for an oximeter probe having an LED circuit including LEDs and a photodiode circuit including a photodiode, comprising; means for electrically activating the LED circuit and the photodiode circuit of the oximeter probe so as to produce electrical test output signals in the circuits that are representative of the continuity of the circuits, means for sensing whether or not the test output signals are present in the circuits, means for electrically activating the LEDs of the oximeter probe so as to produce electrical test output signals on the photodiode that are representative of the sensitivity of the photodiode, means for sensing the test output signals on the photodiode, and means for selectively and separately displaying an indication of the test output signals that are representative of the continuity of the circuits and the test output signals that are representative of the sensitivity of
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61. signals. .Iaddend..Iadd.82. A method for testing a pulse oximeter with a testing instrument wherein the oximeter includes a probe, an LED driver, a signal processor, an oximeter interface connector connected to the signal processor and the LED driver, the probe including LEDs, a photodiode, and a probe connector connected to the oximeter interface connector in normal use of the oximeter, the LEDs being responsive to LED drive signals from the LED driver and the photodiode generating SpO2 waveforms for delivery to the signal processor through the oximeter interface connector when the probe is attached to the human being, and wherein the testing instrument includes a housing, a probe testing connector mounted on the housing, and a simulator testing connector mounted on the housing, the method comprising the steps of:
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connecting either the probe connector alone to the probe testing connector, the simulator testing connector alone to the oximeter interface connector, or both the probe connector and the simulator testing connector, respectively, to the probe testing connector and the oximeter interface connector; with the simulator testing connector connected to the oximeter interface connector in place of the probe, generating first test signals representative of SpO2 waveforms that simulate said human SpO2 waveforms generated by the probe in response to said LED drive signals; transmitting the first test signals to the signal processor through the interconnected simulator testing connector and oximeter interface connector; with the probe connector connected to the probe testing connector instead of to the oximeter interface connector, generating a second test signal independently of the LED driver; transmitting the second test signal to the probe through the interconnected probe connector and probe testing connector; receiving an output from the probe in response to the second test signal; and
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62. displaying said output. .Iaddend..Iadd.83. A method for testing either the continuity or the sensitivity or both of a pulse oximeter probe that has an LED circuit including red and IR LEDs, a photodiode circuit including a photodiode, and a probe connector, the method involving the use of a housing enclosing electrically activating sources and signal sensing circuitry and mounting a probe testing connector providing LED and photodiode terminals connected to the electrically activating sources and the signal sensing circuitry, the method comprising the steps of:
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interconnecting the probe connector and the probe testing connector and thereby interconnecting the LED and photodiode terminals and the LED and photodiode circuits respectively; electrically activating both of the LED and photodiode circuits with an electrical activating source in the housing if continuity is being tested; electrically activating only the LED circuits with an electrical activating source in the housing if sensitivity is being tested; sensing both of the LED and photodiode circuits for outputs in response to said electrical activation if continuity is being tested; sensing the photodiode circuit for outputs in response to said electrical activation if sensitivity is being tested; displaying visual indications of the outputs that are sensed, and determining the continuity and/or sensitivity of the probe from said visual indications. .Iaddend.
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Specification