CN103767712B - A kind of blood oxygen measuring device of environment resistant light interference and method thereof - Google Patents
A kind of blood oxygen measuring device of environment resistant light interference and method thereof Download PDFInfo
- Publication number
- CN103767712B CN103767712B CN201410009754.3A CN201410009754A CN103767712B CN 103767712 B CN103767712 B CN 103767712B CN 201410009754 A CN201410009754 A CN 201410009754A CN 103767712 B CN103767712 B CN 103767712B
- Authority
- CN
- China
- Prior art keywords
- current
- signal
- voltage
- resistance
- modular converter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
The blood oxygen measuring device of a kind of environment resistant light interference of the present invention, is provided with: light emitting module, Optical Receivers, current/voltage modular converter, analog-to-digital conversion module, signal processing module; Also be provided with compensating module, this compensating module is arranged between Optical Receivers and current/voltage modular converter, and be connected with Optical Receivers, current/voltage modular converter, signal processing module respectively, for the signal exported according to signal processing module, the stray light electric current that Optical Receivers described in filtering exports; Because compensating module is directly connected with Optical Receivers, directly can connect the stray light electric current of output by filtering light, source avoid being mixed into of stray light electric current, effectively raises the signal to noise ratio of measuring device; And the blood oxygen measuring method of a kind of environment resistant light interference of corresponding structure of the present invention has above-mentioned advantage too.
Description
Technical field
The present invention relates to a kind of noinvasive blood oxygen measurement device, particularly relate to blood oxygen measuring device and the measuring method thereof of the interference of a kind of environment resistant light.
Background technology
Blood oxygen is blood oxygen saturation again, and blood oxygen saturation weighs the important parameter that blood of human body carries the ability of oxygen, by the measurement of blood oxygen saturation, can understand the oxygen content of patient in time, have epochmaking clinical value.
Noinvasive Oximetry mainly adopts photoelectric technology, usually has two kinds of methods: projective method and bounce technique.Photoelectric technology is by launching light beam by exposing to the specific part of human body, light is by transmission or reflex to Optical Receivers, the photo-signal intensity that different blood oxygen saturations and different pulse frequencies all can cause Optical Receivers to produce is different, can detect blood oxygen saturation and pulse frequency accordingly.
The testing circuit of blood oxygen all comprises current/voltage conversion (namely electric current turns voltage) circuit, the usual way of this conversion adopts operational amplifier to realize, for realizing high signal to noise ratio, we wish that this circuit has signal gain large as far as possible usually, when namely receiving maximum photoelectric current, the voltage that current/voltage modular converter exports should close to the maximum output voltage of operational amplifier.But under practical situation, because the spectrum of external environmental light (sunlight, houselights, medical light source etc.) for disease treatment has overlapping part with the receiving spectrum of Optical Receivers, so when these illumination are mapped to Optical Receivers, photoelectric current will inevitably be produced, the photoelectric current generation aliasing that these photoelectric currents produce with light emitting module in measurement, the error of measuring circuit is also increased while photo-current intensity significantly promotes, the operational amplifier in current/voltage modular converter can be caused time the most serious saturated, cause Oximetry to lose efficacy.
And ambient light rejection unit carries out interference filtering based on the mode of voltage at present, this must be provided with current/voltage modular converter before this ambient light rejection unit, is its conversion and process optical signal.Be easily current/voltage modular converter saturated while, also inevitable light interfering signals are treated to useful signal, thus cause blood oxygen measurement device error large, signal to noise ratio is low, even measures inefficacy.
Summary of the invention
It is relatively simple that the technical problem to be solved in the present invention is to provide a kind of structure, signal to noise ratio high blood oxygen measuring device.
Carry a device for high oxygen pressure environment resistant photo measure, be provided with: for providing the light emitting module of efficient light sources; The refracted light after measured body and reflected light is irradiated and the Optical Receivers being converted to photoelectric current for receiving described light emitting module; Be connected with described Optical Receivers, the photoelectric current for being exported converts the current/voltage modular converter of photovoltage to; Be connected with described current/voltage modular converter, the analogue signal for being exported is converted to the analog-to-digital conversion module of digital signal; Be connected with described analog-to-digital conversion module, the digital signal for exporting it carries out the signal processing module of respective algorithms process;
Also be provided with compensating module, this compensating module is arranged between described Optical Receivers and described current/voltage modular converter, and be connected with described Optical Receivers, described current/voltage modular converter, described signal processing module respectively, for the signal exported according to described signal processing module, the stray light electric current that Optical Receivers described in filtering exports.
Further, described compensating module includes D/A converting circuit, signal conditioning circuit, current injection circuit;
Described D/A converting circuit is connected with described signal processing module, described signal conditioning circuit respectively, and the compensating signal for being inputted by described signal processing module is converted to analog signal output to described signal conditioning circuit;
Described signal conditioning circuit comprises: the first operational amplifier, the first electric capacity, the second electric capacity, the 3rd electric capacity, the 4th electric capacity, the first resistance, the second resistance, the 3rd resistance, ground terminal, output voltage terminal Vref;
Described first resistance one end is connected to described D/A converting circuit, and the other end is connected serially to the first operational amplifier reverse input end; Described first operational amplifier output terminal and described 3rd resistance, described Vref lead-out terminal, described 3rd electric capacity, described ground terminal sequential series; Described 4th Capacitance parallel connection is in described 3rd electric capacity two ends; Described second Capacitance parallel connection is in the reverse input end of described first operational amplifier and outfan; Described second resistor coupled in parallel is in described first operational amplifier reverse input end and described output voltage terminal Vref; Described first Capacitance parallel connection is in described second resistance two ends; Described first operational amplifier non-inverting input is connected with described ground wire terminal;
Described current injection circuit is provided with the 8th resistance, and described 8th resistance one end is connected to described output voltage terminal Vref, the node between other end access Optical Receivers and current/voltage modular converter; Signal for inputting according to described D/A converting circuit exports offset current to described current/voltage modular converter.
Further, described current/voltage modular converter also comprises auxiliary current voltage conversion unit; Described auxiliary current voltage conversion unit is connected with described Optical Receivers, described signal processing module respectively, for providing many one group of translation interfaces;
Described current injection circuit is also provided with the 9th resistance, for providing many pulse current injectingt interfaces.
Improve as one, described compensating module also comprises signal inversion circuit;
Described signals reverse circuit comprises the 4th resistance, the 5th resistance, the second operational amplifier, the common-mode voltage terminal Vcom of described current/voltage modular converter;
Described 4th resistance one end is connected to described output voltage terminal Vref, and the other end is connected to the second operational amplifier reverse input end; Described 5th resistor coupled in parallel is between described second operational amplifier reverse input end and the second operational amplifier output terminal; Described common-mode voltage connecting terminals is connected to described second operational amplifier non-inverting input; Described 9th resistance one end is connected to the second operational amplifier output terminal, node between other end access Optical Receivers and auxiliary current voltage conversion unit, voltage for exporting described output voltage terminal Vref carries out anti-phase centered by the common-mode voltage Vcom of described current/voltage modular converter, produces the voltage of a pair symmetry centered by the common-mode voltage Vcom of described current/voltage modular converter.
Moreover described 8th resistance and described 9th resistance are set to trimmable resistance.
Further, also Signal-regulated kinase is provided with between described current/voltage modular converter and described analog-to-digital conversion module, described Signal-regulated kinase is connected with described current/voltage modular converter, described analog-to-digital conversion module respectively, for when in analog-to-digital conversion module not integrated filtering and amplifying circuit time, the photoelectric signal that described current/voltage modular converter exports is amplified and/or filtering operation, and exports to described analog-to-digital conversion circuit.
Put forward a method for high oxygen pressure environment resistant photo measure, comprise following sequential steps:
The step of setting DC component threshold value;
Start the step of light emitting module;
Start the step of Optical Receivers;
By the digitized step of photoelectric current that Optical Receivers exports;
Extract the step of DC component in photoelectric current digital signal;
Judge the step of described DC component whether over range;
If described DC component goes beyond the scope, then perform following steps:
The step of adjustment compensation dosage size;
By the step that adjustment post-compensation amount compensates;
Restart the step extracting DC component in photoelectric current digital signal;
If described DC component does not go beyond the scope, then return the step of DC component in described extraction photoelectric current digital signal.
Further, further comprising the steps of in the described step compensated by adjustment post-compensation amount:
By the compensating direct current component that described adjustment post-compensation amount input is contrary with described DC component voltage.
Further, further comprising the steps of in the step of described setting DC component threshold value:
Select the step of whether manually input;
If selecting is then manually input;
If you select No, then the step of input is automatically started.
Further, further comprising the steps of in the step that described startup inputs automatically:
Close the step of light emitting module;
Start the step of Optical Receivers;
By the step of the stray light current digital that Optical Receivers exports;
Extract the step disturbing DC component in stray light current digital signal;
By the step that described interference DC component treatment is described DC component threshold value.
The blood oxygen measuring device of a kind of environment resistant light interference of the present invention is by adopting based on adjusting the compensating module of electric current simultaneously, avoid and increase signal conversion unit before compensating module, and the error that measurement device causes the process of interfering signal is avoided from source, improve measurement accurately, the blood oxygen measuring device of a kind of environment resistant light interference of the present invention is made to have the scope of application widely, overcome deficiency of the prior art, and the blood oxygen measuring method of a kind of environment resistant light interference of corresponding structure of the present invention has above-mentioned advantage too.
Accompanying drawing explanation
For ease of illustrating, the present invention is described in detail by following detailed description of the invention and accompanying drawing.
Fig. 1 is the basic structure schematic diagram of the blood oxygen measuring device of a kind of environment resistant light interference of the present invention;
Fig. 2 is the modified node method schematic diagram of the blood oxygen measuring device of a kind of environment resistant light interference of the present invention;
Fig. 3 is the basic schematic diagram of the blood oxygen measuring method of a kind of environment resistant of the present invention light interference;
Fig. 4 is the improvement schematic diagram of the blood oxygen measuring method of a kind of environment resistant light interference of the present invention;
Fig. 5 is the circuit diagram of the compensating module of the blood oxygen measuring device of a kind of environment resistant light interference of the present invention;
Fig. 6 is the improvement circuit diagram of the compensating module of the blood oxygen measuring device of a kind of environment resistant light interference of the present invention;
Fig. 7 is the signal processing module workflow schematic diagram of the blood oxygen measuring device of a kind of environment resistant light interference of the present invention.
Detailed description of the invention
In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.
As shown in accompanying drawing 1-7, a kind of device carrying high oxygen pressure environment resistant photo measure, is provided with: for providing the light emitting module 101 of efficient light sources; The refracted light after measured body and reflected light is irradiated and the Optical Receivers 102 being converted to photoelectric current for receiving described light emitting module 101; Be connected with described Optical Receivers 102, the photoelectric current for being exported converts the current/voltage modular converter 104 of photovoltage to; Be connected with described current/voltage modular converter 104, the analogue signal for being exported is converted to the analog-to-digital conversion module 106 of digital signal; Be connected with described analog-to-digital conversion module 106, the digital signal for exporting it carries out the signal processing module 107 of respective algorithms process.
Also be provided with compensating module 103, this compensating module 103 is arranged between described Optical Receivers 102 and described current/voltage modular converter 104, and be connected with described Optical Receivers 102, described current/voltage modular converter 104, described signal processing module 107 respectively, for the signal exported according to described signal processing module 107, the stray light electric current that Optical Receivers 102 described in filtering exports.
Further, described compensating module 103 includes D/A converting circuit 301, signal conditioning circuit 302, current injection circuit 304.
Described D/A converting circuit 301 is connected with described signal processing module 107, described signal conditioning circuit 302 respectively, and the compensating signal for being inputted by described signal processing module 107 is converted to analog signal output to described signal conditioning circuit 302.
Described signal conditioning circuit 302 comprises: the first operational amplifier opa1, the first electric capacity c1, the second electric capacity c2, the 3rd electric capacity c3, the 4th electric capacity c4, the first resistance r1, the second resistance r2, the 3rd resistance r3, ground terminal, output voltage terminal Vref lead-out terminal 0.
Described first resistance r1 one end is connected to D/A converting circuit 301, and the other end is connected serially to the reverse input end of the first operational amplifier opa1; Described first operational amplifier output terminal and described 3rd resistance r3, described output voltage terminal Vref, described 3rd electric capacity c3, described ground terminal 0 sequential series; Described 4th electric capacity c4 is parallel to described 3rd electric capacity c3 two ends; Described second electric capacity c2 is parallel to reverse input end and the outfan of described first operational amplifier opa1; Described second resistance r2 is parallel to described first operational amplifier reverse input end and described output voltage terminal Vref; Described first electric capacity c1 is parallel to described second resistance r2 two ends; The non-inverting input of described first operational amplifier opa1 is connected with described ground wire terminal 0.
Described current injection circuit 304 is provided with the 8th resistance r8, and described 8th resistance r8 one end is connected to described output voltage terminal Vref, the node between other end access Optical Receivers 102 and current/voltage modular converter 104; Signal for inputting according to described D/A converting circuit 301 exports offset current to described current/voltage modular converter 104.
Further, described current/voltage modular converter 104 also comprises auxiliary current voltage conversion unit 1041; Described auxiliary current voltage conversion unit 1041 is connected with described Optical Receivers 102, described signal processing module 107 respectively, for providing many one group of translation interfaces.
Described current injection circuit 304 is also provided with the 9th resistance r9, for providing many pulse current injectingt interfaces.
Improve as one, described compensating module 103 also comprises signals reverse circuit 303.
Described signals reverse circuit 303 comprises the 4th resistance r4, the 5th resistance r5, the second operational amplifier opa2, the common-mode voltage terminal Vcom of described current/voltage modular converter 104.
Described 4th resistance r4 one end is connected to described output voltage terminal Vref, and the other end is connected to the reverse input end of the second operational amplifier opa2; Between the reverse input end that described 5th resistance r5 is parallel to described second operational amplifier opa2 and the outfan of the second operational amplifier opa2; Described common-mode voltage terminal Vcom is connected to the non-inverting input of described second operational amplifier opa2; 9th resistance r9 one end is connected to the outfan of the second operational amplifier opa2, node between other end access Optical Receivers 102 and auxiliary current voltage conversion unit 1041, electric current for exporting described output voltage terminal Vref carries out anti-phase centered by the common-mode voltage of described current/voltage modular converter 104, produces the voltage of a pair symmetry centered by the common-mode voltage of described current/voltage modular converter 104.
Moreover described 8th resistance r8 and described 9th resistance r9 is set to trimmable resistance.
Another step, Signal-regulated kinase 105 is also provided with between described current/voltage modular converter 104 and described analog-to-digital conversion module 106, described Signal-regulated kinase 105 is connected with described current/voltage modular converter 104, described analog-to-digital conversion module 106 respectively, for when in analog-to-digital conversion module 106 during not integrated filtering and amplifying circuit PGA, the photoelectric signal that described current/voltage modular converter 104 exports is amplified and/or filtering operation, and exports described analog-to-digital conversion circuit 106 to.
Put forward a method for high oxygen pressure environment resistant photo measure, comprise following sequential steps:
The step of DC component threshold value is set after opening device;
Start the step of light emitting module 101;
Start the step of Optical Receivers 102;
The digitized step of photoelectric current that Optical Receivers 102 exports by analog-to-digital conversion module 106;
Signal processing module 107 extracts the step of DC component in photoelectric current digital signal;
Signal processing module 107 judges the step of described DC component whether over range;
If described DC component goes beyond the scope, then perform following steps:
Signal processing module 107 adjusts the step of compensation dosage size;
The step that compensating module 103 compensates by adjustment post-compensation amount;
Signal processing module 107 restarts the step extracting DC component in photoelectric current digital signal;
If described DC component does not go beyond the scope, then return the step that described signal processing module 107 extracts DC component in photoelectric current digital signal.
Further, further comprising the steps of in the step that described compensating module 103 compensates by adjustment post-compensation amount:
Compensating module 103 inputs the compensating direct current component contrary with DC component voltage by described adjustment post-compensation amount.
Further, signal processing module 107 sets in the step of DC component threshold value further comprising the steps of:
Whether manually prompting selects the step of input;
If select be, then manual input direct-current component threshold value;
If you select No, then the step of input is automatically started.
Further, further comprising the steps of in the step that described startup inputs automatically:
Close the step of light emitting module 101;
Start the step of Optical Receivers 102;
The step of the stray light current digital that Optical Receivers 102 exports by analog-to-digital conversion module 106;
Signal processing module 107 extracts the step disturbing DC component in stray light current digital signal;
By the step that described interference DC component treatment is described DC component threshold value.
Specifically, as shown in Figure 1, 2:
Light source.This light source is the light that sends of light emitting module 101 and surround lighting and stray light.
Optical Receivers 102.Receive the light that light emitting module 101 sends, also can receive part external environmental light simultaneously; And converting the optical signal received to current signal, this part current signal contains the current signal of light emitting module generation and the disturbance current signal of surround lighting.
Compensating module 103.Compensating module 103 is the adjustable constant-current source circuit of an output current, for offsetting the stray light electric current that surround lighting produces.Compensating circuit comprises D/A converting circuit 301, signal conditioning circuit 302, signal inversion circuit 303, current injection circuit 304 4 element circuits.
Current/voltage modular converter 104.Convert the photoelectric current after compensating to voltage signal, if the current compensation that surround lighting produces is insufficient, the voltage signal exported will containing certain flip-flop, because its amplitude is very low, measuring circuit can not be caused saturated, and signal processing module 107 can process this part interfering signal easily, can ignore in its impact of event.
Signal-regulated kinase 105.This part circuit can amplify and/or filtering operation signal.According to concrete application, if analog-to-digital conversion module (ADC) inside is integrated with amplifier, filtering can carry out hardware filtering or/and carry out digital filtering in signal processing module 107 in current/voltage modular converter 104, and so Signal-regulated kinase 105 can omit.
Analog-to-digital conversion module 106.Analog digital conversion the analogue signal that Signal-regulated kinase 105 exports is converted to digital signal (if Signal-regulated kinase 105 is omitted, then directly convert the signal that current/voltage modular converter 104 exports to digital signal), for the Digital Signal Processing of signal processing module 107 is prepared.
Digital Signal Processing 107.Digital signal analog digital conversion obtained carries out algorithm process, and algorithm process comprises the calculating etc. that control and compensation module 103 exports required offset current and blood oxygen, pulse frequency.
Optical Receivers 102 receives all light sources within the scope of its receiving spectrum, luminous energy is converted to electric energy, namely converts current signal to.
The current signal that Optical Receivers 102 exports contains the photoelectric current of light emitting module generation or/and the stray light electric current of surround lighting generation.
Only a kind of light with certain size of current, certain frequency, certain dutycycle that light emitting module 101 is launched, after human body specific part, Optical Receivers 102 converts the light of reception to current signal, and this electric current is square wave, crest has certain amplitude, and trough is 0.
In the measuring process of blood oxygen, surround lighting converts electric current to after being received by Optical Receivers 102, but because of surround lighting conversion slowly, can think that this part electric current is DC current.So, when there is ambient light effects, the electric current that Optical Receivers 102 exports is have certain biased square wave current signal, the trough of its square wave is the photoelectric current of surround lighting generation, and crest to trough electric current is the photoelectric current produced after the light therethrough human body specific part of light emitting module 102.
Compensating module 103 is an adjustable constant-current source circuit for generating, the electric current that make use of surround lighting generation is the feature of direct current, output signal according to signal processing module, export an electric current equal with surround lighting to be offset, the photoelectric current produced after the light therethrough human body specific part of so remaining electric current just only remaining light emitting module.
The present invention devises a closed-loop control system, the disturbance current signal received by signal processing module 107, calculate the interference DC component of this photoelectric current, then export a corresponding with it compensating direct current component by offset current to offset, so just, achieve the compensation under different ambient light photograph, improve accuracy and the reliability of Oximetry.
After compensating, the photoelectric current of the only light therethrough human body specific part generation of remaining light emitting module, namely the trough of square wave current is 0.In the control of reality, the electric current that surround lighting produces has allowed a small amount of residue, and remainder processes by 107.
Embodiment one
As shown in Figure 5, compensating circuit comprises D/A converting circuit (DAC) 301, signal conditioning circuit 302, current injection circuit 304 3 element circuits, current/voltage modular converter 104 is comparatively general current-to-voltage converting circuit, Signal-regulated kinase 105 pairs of signals carry out programming amplifying to meet the demand of unlike signal intensity, and directly carry out analog digital conversion to signal.This embodiment does not have specialized designs Signal-regulated kinase 105, only carries out simple filtering by C5 in figure to signal.The program is for one-terminal current change-over circuit, and so-called one-terminal current conversion and current/voltage modular converter 104 are input as single-ended.Offset current formula is:
.
D/A converting circuit (DAC) 301, exports adjustable voltage.The a reference source that analog-digital converter uses, figure place determine output voltage precision and voltage-regulation step-length.Such as, the analog-digital converter of 12, a reference source is 2.5V, so,
Adjustable digital quantity is:
Output voltage precision is:
Adjustment step-length is:
Therefore, need according to the suitable analog-digital converter of concrete Oximetry application choice, usually use the inner integrated analog-digital converter of microcontroller (107) to meet the demands.
Signal conditioning circuit 302, amplifies and Filtering Processing 301 output voltages, and to reduce signal noise, this circuit output voltage Vref represents.If 301 output noises are very low, so this part circuit can be removed.
Current injection circuit 304, is also referred to as voltage x current (i.e. V-I voltage transitions electric current) change-over circuit.This circuit is realized by resistance R8 or R8, the R9 that one or two resistance is identical, and the voltage that R8, R9 resistance and signal conditioning circuit 302 export determines the size of offset current jointly, can derive offset current formula by circuit diagram:
,
,
,
determined by concrete application,
maximum at least can be designed into 15uA, and this design circuit still can obtain high signal to noise ratio, can meet again the measurement under ambient light of blood oxygen.
Current/voltage modular converter 104, this circuit converts current signal to voltage signal, and this is current detecting common practice.Because front stage circuits compensates the photoelectric current that surround lighting produces, therefore electric current can be changed multiple to improve, namely improve the resistance of R10, R11, realize higher signal to noise ratio by the amplification improving first order circuit, this is also the object that patent of the present invention will reach.
Analog to digital conversion circuit 106, the analog-digital converter device inside that this circuit uses is integrated with gain-programmed amplifier (PGA), by this circuit realiration unlike signal gain of software control, to meet the application under blood oxygen different measuring environment.Signal amplify after and carry out analog digital conversion, for Digital Signal Processing (107) is prepared.
Microcontroller 107, realizes Digital Signal Processing and peripheral circuit controls.
Embodiment two
As shown in Figure 6, compensating circuit comprises D/A converting circuit (DAC) 301, signal conditioning circuit 302, signal inversion circuit 303, current injection circuit 304 4 element circuits.Consistent with embodiment, current/voltage modular converter 104 is comparatively general current-to-voltage converting circuit, and 106 pairs of signals carry out programming amplifying to meet the demand of unlike signal intensity, and directly carry out analog digital conversion to signal.This embodiment does not have specialized designs signal conditioning circuit, only carries out simple filtering by C5, C8 in figure to signal.This embodiment is for double-ended current type change-over circuit, and namely so-called double-ended current type conversion 104 is input as both-end.
Signal inversion circuit 303, circuit carries out anti-phase to the signal after 302 process centered by common-mode voltage Vcom, is intended to the voltage of generation a pair symmetry centered by common-mode voltage Vcom.Wherein common-mode voltage terminal Vcom is the common-mode voltage of current/voltage modular converter 104.
About the job step of signal processing module, as shown in Figure 7, be specially:
Extract DC component 501 in signal.In Oximetry, luminous tube fluorescent lifetime section is known, accordingly, the DC component in signal can be extracted in the non-glow phase of luminous tube, in this stage, the mode be averaging by single-point sampling, multiple spot all can obtain the DC quantity of signal, and the latter has good inhibitory action to burr in signal, therefore recommends to adopt the latter.
Judge DC component whether over range 502.The DC component obtain 501 steps and the threshold value (setting of this threshold value is obtained by concrete hardware circuit, experimental verification) of setting contrast, if DC component is within threshold range, then do not carry out any operation, re-execute 501 steps; If DC component is in outside threshold range, so just need the size adjusting compensation dosage, until DC component is within threshold range.
Adjustment compensation dosage size 503.In algorithm, corresponding relation is established to DC component and compensation dosage size, this enumerate wherein a kind of corresponding relation to show explanation:
Suppose that compensation dosage size D represents, its scope is 0 ~
, n is 301(analog-digital converter) figure place; Suppose that 401 DC component detected are A, its scope is 0 ~
,
for the DC component produced under maximum surround lighting.Namely, when detecting that DC component A is 0, compensation dosage D is adjusted to 0; When detecting that DC component A is
time, compensation dosage D is adjusted to
.Accordingly, DC component and compensation dosage size corresponding relation can be derived:
By this corresponding relation, the DC component obtained using 501 steps, as foundation, makes compensating module 301 export DC component in corresponding compensation dosage automotive resistance signal by adjustment compensation dosage.
The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all do in the spirit and principles in the present invention any amendment, equivalent to replace and improvement etc., all should be included in protection scope of the present invention.
Claims (10)
1. a blood oxygen measuring device for environment resistant light interference, is provided with: for providing the light emitting module of efficient light sources; The refracted light after measured body and reflected light is irradiated and the Optical Receivers being converted to photoelectric current for receiving described light emitting module; Be connected with described Optical Receivers, the photoelectric current for being exported converts the current/voltage modular converter of photovoltage to; Be connected with described current/voltage modular converter, the analogue signal for being exported is converted to the analog-to-digital conversion module of digital signal; Be connected with described analog-to-digital conversion module, the digital signal for exporting it carries out the signal processing module of respective algorithms process;
It is characterized in that, also be provided with compensating module, this compensating module is arranged between described Optical Receivers and described current/voltage modular converter, and be connected with described Optical Receivers, described current/voltage modular converter, described signal processing module respectively, for the signal exported according to described signal processing module, the stray light electric current that Optical Receivers described in filtering exports.
2. the blood oxygen measuring device of a kind of environment resistant light interference according to claim 1, it is characterized in that, described compensating module includes D/A converting circuit, signal conditioning circuit, current injection circuit;
Described D/A converting circuit is connected with described signal processing module, described signal conditioning circuit respectively, and the compensating signal for being inputted by described signal processing module is converted to analog signal output to described signal conditioning circuit;
Described signal conditioning circuit comprises: the first operational amplifier, the first electric capacity, the second electric capacity, the 3rd electric capacity, the 4th electric capacity, the first resistance, the second resistance, the 3rd resistance, ground terminal, output voltage terminal;
Described first resistance one end is connected to described D/A converting circuit, and the other end is connected serially to the first operational amplifier reverse input end; Described first operational amplifier output terminal and described 3rd resistance, described output voltage terminal, described 3rd electric capacity, described ground terminal sequential series; Described 4th Capacitance parallel connection is in described 3rd electric capacity two ends; Described second Capacitance parallel connection is in the reverse input end of described first operational amplifier and outfan; Described second resistor coupled in parallel is in described first operational amplifier reverse input end and described output voltage terminal; Described first Capacitance parallel connection is in described second resistance two ends; Described first operational amplifier non-inverting input is connected with ground wire terminal;
Described current injection circuit is provided with the 8th resistance, and described 8th resistance one end is connected to described output voltage terminal, and the other end accesses the node between described Optical Receivers and described current/voltage modular converter; Signal for inputting according to described D/A converting circuit exports offset current to described current/voltage modular converter.
3. the blood oxygen measuring device of a kind of environment resistant light interference according to claim 2, it is characterized in that, described current/voltage modular converter also comprises auxiliary current voltage conversion unit; Described auxiliary current voltage conversion unit is connected with described Optical Receivers, described signal processing module respectively, for providing many one group of translation interfaces;
Described current injection circuit is also provided with the 9th resistance, for providing many pulse current injectingt interfaces.
4. the blood oxygen measuring device of a kind of environment resistant light interference according to claim 3, it is characterized in that, described compensating module also comprises signal inversion circuit;
Described signals reverse circuit comprises the 4th resistance, the 5th resistance, the second operational amplifier, the common-mode voltage terminal of described current/voltage modular converter;
Described 4th resistance one end is connected to described output voltage terminal, and the other end is connected to the second operational amplifier reverse input end; Described 5th resistor coupled in parallel is between described second operational amplifier reverse input end and the second operational amplifier output terminal; Described common-mode voltage connecting terminals is connected to described second operational amplifier non-inverting input; Described 9th resistance one end is connected to the second operational amplifier output terminal, node between other end access Optical Receivers and auxiliary current voltage conversion unit, electric current for exporting described output voltage terminal carries out anti-phase centered by the common-mode voltage of described current/voltage modular converter, produces the voltage of a pair symmetry centered by the common-mode voltage of described current/voltage modular converter.
5. the blood oxygen measuring device of a kind of environment resistant light interference according to claim 4, it is characterized in that, described 8th resistance and described 9th resistance are set to trimmable resistance.
6. the blood oxygen measuring device of a kind of environment resistant light interference according to claim 5, it is characterized in that, also Signal-regulated kinase is provided with between described current/voltage modular converter and described analog-to-digital conversion module, described Signal-regulated kinase is connected with described current/voltage modular converter, described analog-to-digital conversion module respectively, for when in analog-to-digital conversion module not integrated filtering and amplifying circuit time, the photoelectric signal that described current/voltage modular converter exports is amplified and/or filtering operation, and exports to described analog-to-digital conversion circuit.
7. a method for the Oximetry of environment resistant light interference, is characterized in that, comprise following sequential steps:
The step of setting DC component threshold value;
Start the step of light emitting module;
Start the step of Optical Receivers;
By the digitized step of photoelectric current that Optical Receivers exports;
Extract the step of DC component in photoelectric current digital signal;
Judge the step of described DC component whether over range;
If described DC component goes beyond the scope, then perform following steps:
The step of adjustment compensation dosage size;
By the step that adjustment post-compensation amount compensates;
Restart the step extracting DC component in photoelectric current digital signal;
If described DC component does not go beyond the scope, then return the step of DC component in described extraction photoelectric current digital signal.
8. the method for the Oximetry of a kind of environment resistant light interference according to claim 7, is characterized in that, further comprising the steps of in the described step compensated by adjustment post-compensation amount:
By the compensating direct current component that described adjustment post-compensation amount input is contrary with described DC component voltage.
9. the method for the Oximetry of a kind of environment resistant light interference according to claim 8, is characterized in that, further comprising the steps of in the step of described setting DC component threshold value:
Select the step of whether manually input;
If selecting is then manually input;
If you select No, then the step of input is automatically started.
10. the method for the Oximetry of a kind of environment resistant light interference according to claim 9, is characterized in that, further comprising the steps of in the step that described startup inputs automatically:
Close the step of light emitting module;
Start the step of Optical Receivers;
By the step of the stray light current digital that Optical Receivers exports;
Extract the step disturbing DC component in stray light current digital signal;
By the step that described interference DC component treatment is described DC component threshold value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410009754.3A CN103767712B (en) | 2014-01-09 | 2014-01-09 | A kind of blood oxygen measuring device of environment resistant light interference and method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410009754.3A CN103767712B (en) | 2014-01-09 | 2014-01-09 | A kind of blood oxygen measuring device of environment resistant light interference and method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103767712A CN103767712A (en) | 2014-05-07 |
| CN103767712B true CN103767712B (en) | 2015-10-21 |
Family
ID=50560798
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410009754.3A Active CN103767712B (en) | 2014-01-09 | 2014-01-09 | A kind of blood oxygen measuring device of environment resistant light interference and method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103767712B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104107051B (en) * | 2014-07-31 | 2017-01-11 | 中国科学院自动化研究所 | Portable multiple brain region blood oxygen detection and real-time display system |
| CN104856697B (en) * | 2015-06-15 | 2017-09-22 | 康泰医学系统（秦皇岛）股份有限公司 | Reflectance oximetry finger identification method |
| CN105910632B (en) * | 2016-04-21 | 2018-10-26 | 矽力杰半导体技术(杭州)有限公司 | Optoelectronic detecting device and integrated circuit |
| CN111741714A (en) * | 2018-01-29 | 2020-10-02 | 深圳迈瑞生物医疗电子股份有限公司 | Blood oxygen measuring system and method |
| CN111665460B (en) * | 2020-05-29 | 2021-07-06 | 南方电网数字电网研究院有限公司 | Sensor direct-current component compensation method and device and sensor device |
| CN113040777B (en) * | 2021-03-25 | 2023-09-22 | 中国科学院空天信息创新研究院 | Multimode physiological signal sensor interface chip, detector and brain state monitor |
| CN114384314A (en) * | 2021-12-31 | 2022-04-22 | 芯海科技（深圳）股份有限公司 | Signal detection circuit, method, integrated circuit, detection device and electronic equipment |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7190985B2 (en) * | 2004-02-25 | 2007-03-13 | Nellcor Puritan Bennett Inc. | Oximeter ambient light cancellation |
| US7649220B2 (en) * | 2007-03-29 | 2010-01-19 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Photodetector having dark current correction |
| US8204567B2 (en) * | 2007-12-13 | 2012-06-19 | Nellcor Puritan Bennett Llc | Signal demodulation |
| EP2288053A1 (en) * | 2009-08-19 | 2011-02-23 | Mechaless Systems GmbH | Optical receiver for receiving light |
| CN102512178B (en) * | 2011-12-23 | 2014-04-09 | 深圳市理邦精密仪器股份有限公司 | Blood oxygen measurer and method |
-
2014
- 2014-01-09 CN CN201410009754.3A patent/CN103767712B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN103767712A (en) | 2014-05-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103767712B (en) | A kind of blood oxygen measuring device of environment resistant light interference and method thereof | |
| USRE48996E1 (en) | Circuit architecture for mode switch | |
| CN203693603U (en) | Environment-light-interference-resisting blood oxygen measuring equipment | |
| CN203772930U (en) | Weak current signal detection system | |
| CN218006205U (en) | Optical acquisition amplifying circuit and device | |
| CN102890177A (en) | Signal intensity detection circuit of trans-impedance amplifier | |
| CN108363445B (en) | Signal drift dynamic correction method and device | |
| CN107816938B (en) | Circuit for automatically zeroing and modulating amplitude of interference system under low contrast and using method thereof | |
| CN202714854U (en) | Photoelectric detection circuit, blood oxygen probe and monitor | |
| CN102684778B (en) | Infrared receiver and method for improving frequency response of input end of infrared receiver | |
| CN109600122A (en) | Variable trans-impedance amplifier current-voltage conversion circuit | |
| CN212904654U (en) | Measuring circuit for oxidation-reduction potential | |
| CN109596583A (en) | Bioluminescence device for fast detecting | |
| CN106066397B (en) | A kind of compensation system, method and immunity analysis instrument suitable for current-output type photomultiplier tube | |
| CN208874546U (en) | Bridge circuit zero offset on-line correction circuit based on electric current injection | |
| CN214503885U (en) | Laser receiving circuit for indoor TOF ranging and positioning system | |
| CN116026215A (en) | Light spot position detection system based on graphene-germanium-based position sensitive detector | |
| CN112857566A (en) | Anti-sunlight infrared photoelectric detection circuit | |
| CN211206736U (en) | Battery noise testing device | |
| CN212059134U (en) | Device and circuit for measuring laser pulse energy | |
| CN114244363A (en) | Microcurrent IV conversion device and method | |
| CN111812187B (en) | Multithreading integrated main control system applied to FAIMS | |
| CN103674241A (en) | Photosensitive circuit for detecting photosensitive signal | |
| CN114034384A (en) | Photoelectric sampling assembly and wearable equipment | |
| CN203122375U (en) | Non-invasive blood pressure anti-interference circuit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |