CN205433689U - Breathe measuring circuit and carrier wave generating circuit thereof - Google Patents
Breathe measuring circuit and carrier wave generating circuit thereof Download PDFInfo
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- CN205433689U CN205433689U CN201620014237.XU CN201620014237U CN205433689U CN 205433689 U CN205433689 U CN 205433689U CN 201620014237 U CN201620014237 U CN 201620014237U CN 205433689 U CN205433689 U CN 205433689U
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Abstract
The utility model provides a breathe measuring circuit and carrier wave generating circuit, relate to breathing and measure technical field. This carrier wave generating circuit makes it switch between low level and low noise voltage with control circuit who forms the square wave and the noise voltage 2 who is used for carrying on two way noise voltage 1 of noise voltage 0 to two tunnel symmetry square waves that switch circuit exported including low noise voltage source, the switch circuit who is used for low two tunnel symmetry square waves of noise voltage output of basis who is used for producing low noise voltage, the output voltage who is used for controlling switch circuit, the output in low noise voltage source links to each other with switch circuit's input, and two outputs of switch circuit are continuous with two inputs of filter circuit respectively, and switch circuit's control end links to each other with control circuit's output. The utility model discloses can ensure that carrier wave generating circuit exports the carrier signal who has high SNR to can reduce to breathe and measure circuit noise, improve the SNR of breathing the measuring circuit.
Description
Technical field
This utility model belongs to respiration measurement technical field, particularly relates to a kind of respiration measurement circuit and carrier generating circuit thereof.
Background technology
Breathing is the process of gas exchange between body and external environment, by respiration measurement, it can be realized that its physiologic information behind, thus has important clinical value.
At present, the method for respiration measurement mainly has: pressure transducer method, temperature sensor method and impedance method, wherein impedance method is most widely used in respiration measurement equipment.Impedance method make use of the characteristic of " during body respiratory movement, cavity deformation, the electrical impedance of body tissue also can produce respective change ".
Utilizing impedance method to measure in the circuit breathed, most common is to utilize modulation system to measure impedance.Breath signal detection equipment produces the carrier signal of certain frequency, this carrier signal is through conducting wire, it is coupled to tested cavity, when cavity generation respiratory movement, the electrical impedance of body changes therewith, these small impedance variation contain respiration information, simultaneously by carrier modulation, become modulated signal, modulated signal is amplified and demodulates by the late-class circuit of conducting wire, then filters, and extracts breath signal, breath signal enters analog to digital conversion circuit, breath signal is converted to digital signal and is transported to the Digital Signal Processing that microprocessor carries out being correlated with.
As it has been described above, utilize the breath signal measuring circuit of modulation system to have carrier generating circuit, and the outgoing carrier signal quality of carrier generating circuit affects the signal to noise ratio of the breath signal finally obtained.Actual carrier signal is not preferable, has noise, and when carrier signal is modulated to modulated signal, this noise may proceed to exist in modulated signal, when modulated signal is demodulated obtain breath signal time, breath signal will be mixed with this noise.The band a width of 0.1～2.5Hz of breath signal, actual carrier signal can be containing the noise of each frequency range, can be filtered or be converted to by breath signal the laggard line algorithm of digital signal by the filter circuit of hardware higher than the noise of this frequency range to filter, but cannot remove with the noise of frequency domain with breathing bandwidth.In hardware circuit, the noise having overlapping frequency domain with breath signal is low-frequency noise, also referred to as 1/f noise or flicker noise, occurs in all of active device and passive device, the size of this low-frequency noise is inversely proportional to frequency, i.e. frequency more low noise is the biggest.So for the breath signal of low frequency, the noise of impact maximum is low-frequency noise, other noises can be removed by hardware circuit or software filtering.
And carrier generating circuit common in respiration measurement circuit, it is common that controller controls to export square wave with the digit chip such as door or d type flip flop, then square wave is filtered, amplification etc. processes and obtains carrier wave, then carrier wave is exported conducting wire.Also have directly exports square wave by controller, then amplify after filtering obtain carrier wave after output to conducting wire.Owing to low-frequency noise is not taken measures by these circuit, so the carrier signal of output exists the biggest low-frequency noise.These low-frequency noises are amplified along with the amplification of modulated signal, and the signal to noise ratio finally obtaining breath signal is the most relatively low.
To sum up, owing to conventional technology does not recognize the impact on respiration measurement of low-frequency noise that carrier signal contains, the commonly used carrier generating circuit that can produce significantly low-frequency noise, cause the respiratory waveform signal to noise ratio collected low, have impact on measurement effect.
Utility model content
The purpose of this utility model embodiment is to provide a kind of respiration measurement circuit and carrier generating circuit thereof, aim to solve the problem that in prior art due to the commonly used carrier generating circuit that can produce significantly low-frequency noise, cause the respiratory waveform signal to noise ratio collected low, the problem that have impact on measurement effect.
This utility model embodiment is realized in, a kind of carrier generating circuit, including the low noise voltage source for producing low noise voltage, for the on-off circuit according to described low noise voltage output two-way symmetrical square wave, for controlling the output voltage of described on-off circuit, make the output voltage of described on-off circuit switch to be formed the control circuit of square wave between low level and described low noise voltage and the two-way symmetrical square wave for exporting described on-off circuit is filtered exporting the filter circuit of two-way carrier signal；
Wherein, the outfan in described low noise voltage source is connected with the input of described on-off circuit, two outfans of described on-off circuit are connected with two inputs of described filter circuit respectively, and the end that controls of described on-off circuit is connected with the outfan of described control circuit.
In the carrier generating circuit described in this utility model embodiment, also include the voltage follower being connected between outfan and the input of described on-off circuit in described low noise voltage source.
In the carrier generating circuit described in this utility model embodiment, described voltage follower includes the first operational amplifier, the first resistor, the second resistor, the first capacitor and the second capacitor；
The normal phase input end of described first operational amplifier is connected to the outfan in described low noise voltage source, the inverting input of described first operational amplifier is by described first resistor and described second capacitor grounding and outfan and the first end of described second resistor being connected to described first operational amplifier by described second capacitor, and the second end of described second resistor is connected with the common contact of described first resistor and described second capacitor and is connected to the input of described on-off circuit.
In the carrier generating circuit described in this utility model embodiment, described on-off circuit uses integrated two-way 2 to select the switch chip of 1 analog switch function, and described switch chip includes the first logic control pin, the second logic control pin, the first input pin, the second input pin, the first grounding pin, the second grounding pin, the first output pin and the second output pin；
Described first logic control pin and described second logic control pin constitute the end that controls of described on-off circuit and are connected to the outfan of described control circuit, the input that described first input pin and described second input pin constitute described on-off circuit is connected to the outfan in described low noise voltage source, two outfans that described first grounding pin and described second grounding pin ground connection respectively, described first output pin and described second output pin constitute described on-off circuit are respectively connecting to two inputs of described filter circuit.
In the carrier generating circuit described in this utility model embodiment, described on-off circuit includes the first audion, the second audion, the 7th resistor, the 8th resistor and the 9th resistor；
nullThe base stage of described first audion and the first end of described 7th resistor connect the end that controls of the described on-off circuit of composition altogether and are connected to the outfan of described control circuit，Second end of described 7th resistor、The emitter stage of described first audion and the emitter stage of described second audion connect rear ground connection altogether，The base stage of the colelctor electrode of described first audion and described second audion and the first end of described 8th resistor constitute an outfan of described on-off circuit and are connected to an input of described filter circuit after connecing altogether，First end of the colelctor electrode of described second audion and described 9th resistor constitutes another outfan of described on-off circuit and is connected to another input of described filter circuit after connecing altogether，Second end of described 8th resistor and the second end of described 9th resistor constitute the input of described on-off circuit and are connected to the outfan in described low noise voltage source after connecing altogether.
In the carrier generating circuit described in this utility model embodiment, described filter circuit includes that two-way filter unit, first via filter unit include the 3rd capacitor, the 3rd resistor, the 4th resistor and the 3rd operational amplifier；Described second filter unit includes the 4th capacitor, the 5th resistor, the 6th resistor and four-operational amplifier；
nullFirst end of described 3rd capacitor and the first end of described 4th capacitor respectively constitute two inputs of described filter circuit and are connected to two outfans of described on-off circuit，Second end of described 3rd capacitor is connected to the inverting input of described 3rd operational amplifier and the common junction of described 4th resistor by described 3rd resistor，The positive input end grounding of described 3rd operational amplifier，The outfan of described 3rd operational amplifier and the second end of described 4th resistor constitute an outfan of described filter circuit and export a road carrier signal after connecing altogether，Second end of described 4th capacitor is connected to inverting input and first end of described 6th resistor of described four-operational amplifier by described 5th resistor，The positive input end grounding of described four-operational amplifier，The outfan of described positive operational amplifier and the second end of described 6th resistor connect another outfan of the described filter circuit of composition altogether and export another road carrier signal.
In the carrier generating circuit described in this utility model embodiment, described control circuit uses the single-chip microcomputer for exporting certain frequency square wave control signal.
In the carrier generating circuit described in this utility model embodiment, described control circuit uses the oscillating circuit for exporting certain frequency square wave control signal.
The another object of this utility model embodiment is to provide a kind of respiration measurement circuit, including the carrier generating circuit being sequentially connected with, conducting wire, differential amplifier circuit, demodulator circuit, low-pass filter circuit, analog to digital conversion circuit and digital signal processing circuit, wherein: described carrier generating circuit uses the carrier generating circuit described in any of the above-described item.
Respiration measurement circuit and the carrier generating circuit thereof of implementing the offer of this utility model embodiment have the advantages that
This utility model embodiment has the voltage of low noise owing to using the output of low noise voltage source, and the square-wave signal of the low noise voltage output two-way symmetry that on-off circuit exports is controlled according to described low noise voltage source by control circuit, two-way carrier signal is exported after the square-wave signal that two-way is symmetrical being filtered by filter circuit again, owing to two-way carrier signal is directed to the voltage of low noise, therefore the low-frequency noise modulating the carrier signal obtained is the least, ensure that the carrier generating circuit as respiration measurement circuit source has the carrier signal of high s/n ratio, thus reduce respiration measurement circuit noise, improve the signal to noise ratio of respiration measurement circuit, make respiration measurement circuit can measure more faint breath signal.
Accompanying drawing explanation
Fig. 1 is the structural representation of the carrier generating circuit that this utility model first embodiment provides；
Fig. 2 is the circuit fundamental diagram of the carrier generating circuit that this utility model first embodiment provides；
Fig. 3 is the structural representation of the carrier generating circuit that this utility model the second embodiment provides；
Fig. 4 is the circuit fundamental diagram of the carrier generating circuit that this utility model the second embodiment provides；
Fig. 5 is the structural representation of the respiration measurement circuit that this utility model embodiment provides.
Detailed description of the invention
In order to make the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with drawings and Examples, this utility model is further elaborated.Should be appreciated that specific embodiment described herein, only in order to explain this utility model, is not used to limit this utility model.
Fig. 1 is the structural representation of the carrier generating circuit that this utility model first embodiment provides.Illustrate only part related to the present embodiment for convenience of description.
Shown in Figure 1, a kind of carrier generating circuit that the present embodiment provides, including the low noise voltage source 201 for producing low noise voltage, for the on-off circuit 202 according to described low noise voltage output two-way symmetrical square wave, for controlling the output voltage of described on-off circuit 202, make the output voltage of described on-off circuit 202 switch to be formed the control circuit 203 of square wave between low level and described low noise voltage and the two-way symmetrical square wave for export described on-off circuit 202 is filtered the filter circuit 204 of output two-way carrier signal；Wherein, the outfan in described low noise voltage source 201 is connected with the input of described on-off circuit 202, two outfans of described on-off circuit 202 are connected with two inputs of described filter circuit 204 respectively, and the end that controls of described on-off circuit 202 is connected with the outfan of described control circuit 203.
In the present embodiment, described low noise voltage source 201 uses to be had low noise integrated voltage source acquisition low noise voltage or uses the voltage by low-pass filter circuit 204 input that cut-off frequency is 1HZ or lower cut-off frequency to be filtered, and the method for the low-frequency noise reducing by 0.1～2.5HZ frequency range obtains low noise voltage.
Implementing example as one, Fig. 2 shows the circuit fundamental diagram of the carrier generating circuit that the present embodiment provides.Illustrate only part related to the present embodiment for convenience of description.Shown in Figure 2:
In the present embodiment, described on-off circuit 202 includes the first audion Q1, the second audion Q2, the 7th resistor R7, the 8th resistor R8 and the 9th resistor R9；nullThe base stage of described first audion Q1 and first end of described 7th resistor R7 connect the end that controls of the described on-off circuit 202 of composition altogether and are connected to the outfan of described control circuit 203，Second end of described 7th resistor R7、The emitter stage of described first audion Q1 and the emitter stage of described second audion Q2 connect rear ground connection altogether，The base stage of the colelctor electrode of described first audion Q1 and described second audion Q2 and first end of described 8th resistor R8 constitute an outfan of described on-off circuit 202 and are connected to an input of described filter circuit 204 after connecing altogether，The colelctor electrode of described second audion Q2 and first end of described 9th resistor R9 constitute another outfan of described on-off circuit 202 and are connected to another input of described filter circuit 204 after connecing altogether，Second end of described 8th resistor R8 and second end of described 9th resistor R9 constitute the input of described on-off circuit 202 and are connected to the outfan in described low noise voltage source 201 after connecing altogether.Described control circuit 203 uses single-chip microcomputer or oscillating circuit for exporting certain frequency square wave control signal.
Wherein, on-off circuit 202 is made up of the first audion Q1, the second audion Q2, the 7th resistor R7, the 8th resistor R8 and the 9th resistor R9.As in figure 2 it is shown, VA is the voltage of A point, VB is the voltage of B point, the first audion Q1 conducting when control circuit 203 exports high level, voltage VA is approximately equal to 0V, causes the second audion cut-off, and voltage VB is equal to low noise voltage Vref of low noise voltage source 201 output；When control circuit 203 output low level, the first audion Q1 cut-off, voltage VA is equal to low noise voltage Vref, causes the second audion Q2 conducting, and voltage VB is approximately equal to 0V.When control circuit 203 output be square wave level time, VA and VB as the control of control circuit 203 and become square wave, the waveform of VA is anti-phase with the waveform of control circuit 203, the waveform homophase of the waveform of VB and control circuit 203.
In the present embodiment, described filter circuit 204 includes that two-way filter unit, first via filter unit include the 3rd capacitor C3, the 3rd resistor R3, the 4th resistor R4 and the 3rd operational amplifier U3；Described second filter unit includes the 4th capacitor C4, the 5th resistor R5, the 6th resistor R6 and four-operational amplifier U4；nullFirst end of described 3rd capacitor C3 and first end of described 4th capacitor C4 respectively constitute two inputs of described filter circuit 204 and are connected to two outfans of described on-off circuit 202，Second end of described 3rd capacitor C3 is connected to the inverting input of described 3rd operational amplifier U3 and the common junction of described 4th resistor R4 by described 3rd resistor R3，The positive input end grounding of described 3rd operational amplifier U3，The outfan of described 3rd operational amplifier U3 and second end of described 4th resistor R4 constitute an outfan of described filter circuit 204 and export a road carrier signal after connecing altogether，Second end of described 4th capacitor C4 is connected to inverting input and first end of described 6th resistor R6 of described four-operational amplifier U4 by described 5th resistor R5，The positive input end grounding of described four-operational amplifier U4，The outfan of described four-operational amplifier and second end of described 6th resistor R6 connect altogether and constitute another outfan of described filter circuit 204 and export another road carrier signal.
Wherein, first filter unit and the second filter unit constitute the isolation filter circuit with high-pass filtering effect, it is possible not only to the DC component filtering in the two-way square-wave signal of input, to export two-way carrier signal, and may also operate as cushioning effect, it is to avoid the impact on conducting wire of on-off circuit 202 direct impedance.It should be noted that connect the square-wave voltage of the two-way symmetry of on-off circuit 202 output respectively due to the first filter unit in the present embodiment and the second filter unit, therefore this filter circuit 204 can export the carrier signal that two-way is symmetrical.The advantage of the carrier signal that output two-way is symmetrical is, under equal carrier-signal amplitude, the breath signal amplitude that output two-way carrier signal obtains is the twice that single-channel carrier signal obtains breath signal amplitude, the voltage sample utilizing breath signal is so had to process, and for obtaining the breath signal of equal magnitude, it is less that bigger carrier signal makes that the multiple of differential amplifier circuit can arrange, such that it is able to reduce the noise in breath signal further, improves the signal to noise ratio of breath signal.
More than can be seen that, the carrier generating circuit that the present embodiment provides has the voltage of low noise owing to using low noise voltage source 201 output, and the square-wave signal of the low noise voltage output two-way symmetry that on-off circuit 202 exports is controlled according to described low noise voltage source 201 by control circuit 203, two-way carrier signal is exported after the square-wave signal that two-way is symmetrical being filtered by filter circuit 204 again, owing to two-way carrier signal is directed to the voltage of low noise, therefore the low-frequency noise modulating the carrier signal obtained is the least, ensure that the carrier generating circuit as respiration measurement circuit source has the carrier signal of high s/n ratio, thus reduce respiration measurement circuit noise, improve the signal to noise ratio of respiration measurement circuit, make respiration measurement circuit can measure more faint breath signal.
Fig. 3 is the structural representation of the carrier generating circuit that this utility model the second embodiment provides.Fig. 4 is the circuit fundamental diagram of the carrier generating circuit that this utility model the second embodiment provides.Illustrate only part related to the present embodiment for convenience of description.
Shown in Figure 3, relative to a upper embodiment, the carrier generating circuit provided in the present embodiment also includes the voltage follower 205 being connected between outfan and the input of described on-off circuit 202 in described low noise voltage source 201.
Shown in Figure 4, described voltage follower 205 includes the first operational amplifier U1, the first resistor R1, the second resistor R2, the first capacitor C1 and the second capacitor C2；
Wherein, the normal phase input end of described first operational amplifier U1 is connected to the outfan in described low noise voltage source 201, the inverting input of described first operational amplifier U1 is by described first resistor R1 and described second capacitor C2 ground connection and outfan and first end of described second resistor R2 being connected to described first operational amplifier U1 by described second capacitor C2, and second end of described second resistor R2 is connected with the common contact of described first resistor R1 and described second capacitor C2 and is connected to the input of described on-off circuit 202.
In this embodiment, low noise voltage Vref that the output voltage V1 of voltage follower 205 exports with low noise voltage source 201 is equal, i.e. gain is 1, and it can play the effect of buffering.The voltage follower 205 used in the present embodiment is compared with common follower, owing to employing double feedback arrangements of resistance feedback and capacitive feedback, also constitute second-order low-pass filter, thus there is the function of low-pass filtering, and its to filter the effect of low-frequency noise more preferable than the effect of low-pass first order filter circuit.Therefore, it can be seen that owing to increasing by a voltage follower 205 between low noise power supply and on-off circuit 202 in the present embodiment, thus the low-frequency noise in low noise voltage can be reduced further such that it is able to improve the signal to noise ratio of respiration measurement circuit further.
Further, shown in Figure 4, relative to a upper embodiment, on-off circuit 202 in the present embodiment uses integrated two-way 2 to select the switch chip of 1 analog switch function, wherein, described switch chip includes the first logic control pin the 1, second logic control pin the 2, first input pin the 3, second input pin the 6, first grounding pin the 4, second grounding pin the 5, first output pin 7 and the second output pin 8；Described first logic control pin 1 and described second logic control pin 2 constitute the end that controls of described on-off circuit 202 and are connected to the outfan of described control circuit 203, the input that described first input pin 3 and described second input pin 6 constitute described on-off circuit 202 is connected to the outfan in described low noise voltage source 201, described first grounding pin 4 and described second grounding pin 5 ground connection respectively, described first output pin 7 and described second output pin 8 constitute two outfans of described on-off circuit 202 and are respectively connecting to two inputs of described filter circuit 204.
In the present embodiment, when control circuit 203 exports high level, first logic control pin 1 of switch chip and the second logic control pin 2 are high level, now the first output pin 7 of switch chip turns on the first grounding pin 4, the voltage of the first output pin 7 and the voltage of the first grounding pin 4 are identical, are ground voltage；And the second output pin 8 and the second input pin 6 turn on, the voltage of the second output pin 8 and the voltage of the second input pin 6 are identical, are the low noise voltage of low noise power supply output.When control circuit 203 output low level, first logic control pin 1 and the second logic control pin 2 are low level, now the first output pin 7 of switch chip turns on the first input pin 3, the voltage of the first output pin 7 and the voltage of the first input pin 3 are identical, are the low noise voltage of low noise voltage source 201 output；And the second output pin 8 and the second grounding pin 5 turn on, the voltage of the second output pin 8 and the voltage of the second grounding pin 5 are identical, are ground voltage.When control circuit 203 exports the square-wave signal of certain frequency, the first output pin 7 of switch chip switches between the first input pin 3 and the first grounding pin 4, and the voltage of the first output pin 7 also switches between ground voltage and low noise voltage；Second output pin 8 switches between the second input pin 6 and the second grounding pin 5, and the voltage of the second output pin 8 also switches between ground voltage and low noise voltage.Thus, the waveform of the first output pin 7 and the output of the second output pin 8 is square wave, and the voltage magnitude of two-way square wave is identical, frequency is identical, opposite in phase, and the voltage magnitude of two-way square wave is low noise voltage.
It should be noted that control circuit 203, filter circuit 204 in the present embodiment are all identical with control circuit 203 and the filter circuit 204 of offer in first embodiment, therefore it is not repeated at this.
Above it can be seen that the carrier generating circuit that the present embodiment provides can reduce respiration measurement circuit noise equally, improve the signal to noise ratio of respiration measurement circuit so that respiration measurement circuit can measure more faint breath signal.
Fig. 5 is the structural representation of the respiration measurement circuit that this utility model embodiment provides.Illustrate only part related to the present embodiment for convenience of description.
Shown in Figure 5, a kind of respiration measurement circuit that the present embodiment provides, including the carrier generating circuit 101 being sequentially connected with, conducting wire 102, differential amplifier circuit 103, demodulator circuit 104, low-pass filter circuit 105, analog to digital conversion circuit 106 and digital signal processing circuit 107, wherein, described carrier generating circuit 101 uses the carrier generating circuit described in above-mentioned first embodiment or the second embodiment.
In sum, the carrier generating circuit that the respiration measurement circuit that the present embodiment provides provides owing to using first embodiment above or the second embodiment, it can be avoided that the algorithm of hardware filtering and Digital Signal Processing filters the problem that cannot be extracted from the random noise with same frequency by breath signal present in prior art, owing to reducing the low-frequency noise in carrier generating circuit, so that breath signal is more smooth and has higher signal to noise ratio so that this respiration measurement circuit can measure more faint breath signal.
The foregoing is only preferred embodiment of the present utility model, not in order to limit this utility model, all any amendment, equivalent and improvement etc. made within spirit of the present utility model and principle, within should be included in protection domain of the present utility model.
Claims (9)
1. a carrier generating circuit, it is characterized in that, including the low noise voltage source for producing low noise voltage, for the on-off circuit according to described low noise voltage output two-way symmetrical square wave, for controlling the output voltage of described on-off circuit, make the output voltage of described on-off circuit switch to be formed the control circuit of square wave between low level and described low noise voltage and the two-way symmetrical square wave for exporting described on-off circuit is filtered exporting the filter circuit of two-way carrier signal；
Wherein, the outfan in described low noise voltage source is connected with the input of described on-off circuit, two outfans of described on-off circuit are connected with two inputs of described filter circuit respectively, and the end that controls of described on-off circuit is connected with the outfan of described control circuit.
2. carrier generating circuit as claimed in claim 1, it is characterised in that also include the voltage follower being connected between outfan and the input of described on-off circuit in described low noise voltage source.
3. carrier generating circuit as claimed in claim 2, it is characterised in that described voltage follower includes the first operational amplifier, the first resistor, the second resistor, the first capacitor and the second capacitor；
The normal phase input end of described first operational amplifier is connected to the outfan in described low noise voltage source, the inverting input of described first operational amplifier is by described first resistor and described second capacitor grounding and outfan and the first end of described second resistor being connected to described first operational amplifier by described second capacitor, and the second end of described second resistor is connected with the common contact of described first resistor and described second capacitor and is connected to the input of described on-off circuit.
4. carrier generating circuit as claimed in claim 1, it is characterized in that, described on-off circuit uses integrated two-way 2 to select the switch chip of 1 analog switch function, and described switch chip includes the first logic control pin, the second logic control pin, the first input pin, the second input pin, the first grounding pin, the second grounding pin, the first output pin and the second output pin；
Described first logic control pin and described second logic control pin constitute the end that controls of described on-off circuit and are connected to the outfan of described control circuit, the input that described first input pin and described second input pin constitute described on-off circuit is connected to the outfan in described low noise voltage source, two outfans that described first grounding pin and described second grounding pin ground connection respectively, described first output pin and described second output pin constitute described on-off circuit are respectively connecting to two inputs of described filter circuit.
5. carrier generating circuit as claimed in claim 1, it is characterised in that described on-off circuit includes the first audion, the second audion, the 7th resistor, the 8th resistor and the 9th resistor；
nullThe base stage of described first audion and the first end of described 7th resistor connect the end that controls of the described on-off circuit of composition altogether and are connected to the outfan of described control circuit，Second end of described 7th resistor、The emitter stage of described first audion and the emitter stage of described second audion connect rear ground connection altogether，The base stage of the colelctor electrode of described first audion and described second audion and the first end of described 8th resistor constitute an outfan of described on-off circuit and are connected to an input of described filter circuit after connecing altogether，First end of the colelctor electrode of described second audion and described 9th resistor constitutes another outfan of described on-off circuit and is connected to another input of described filter circuit after connecing altogether，Second end of described 8th resistor and the second end of described 9th resistor constitute the input of described on-off circuit and are connected to the outfan in described low noise voltage source after connecing altogether.
6. the carrier generating circuit as described in claim 4 or 5, it is characterised in that described filter circuit includes that two-way filter unit, first via filter unit include the 3rd capacitor, the 3rd resistor, the 4th resistor and the 3rd operational amplifier；Described second filter unit includes the 4th capacitor, the 5th resistor, the 6th resistor and four-operational amplifier；
nullFirst end of described 3rd capacitor and the first end of described 4th capacitor respectively constitute two inputs of described filter circuit and are connected to two outfans of described on-off circuit，Second end of described 3rd capacitor is connected to the inverting input of described 3rd operational amplifier and the common junction of described 4th resistor by described 3rd resistor，The positive input end grounding of described 3rd operational amplifier，The outfan of described 3rd operational amplifier and the second end of described 4th resistor constitute an outfan of described filter circuit and export a road carrier signal after connecing altogether，Second end of described 4th capacitor is connected to inverting input and first end of described 6th resistor of described four-operational amplifier by described 5th resistor，The positive input end grounding of described four-operational amplifier，The outfan of described positive operational amplifier and the second end of described 6th resistor connect another outfan of the described filter circuit of composition altogether and export another road carrier signal.
7. carrier generating circuit as claimed in claim 6, it is characterised in that described control circuit uses the single-chip microcomputer for exporting certain frequency square wave control signal.
8. carrier generating circuit as claimed in claim 6, it is characterised in that described control circuit uses the oscillating circuit for exporting certain frequency square wave control signal.
9. a respiration measurement circuit, including the carrier generating circuit being sequentially connected with, conducting wire, differential amplifier circuit, demodulator circuit, low-pass filter circuit, analog to digital conversion circuit and digital signal processing circuit, it is characterized in that, described carrier generating circuit uses the carrier generating circuit as described in any one of claim 1～8.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201620014237.XU CN205433689U (en) | 2016-01-07 | 2016-01-07 | Breathe measuring circuit and carrier wave generating circuit thereof |
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| CN201620014237.XU CN205433689U (en) | 2016-01-07 | 2016-01-07 | Breathe measuring circuit and carrier wave generating circuit thereof |
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| CN205433689U true CN205433689U (en) | 2016-08-10 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107773240A (en) * | 2016-08-24 | 2018-03-09 | 四川锦江电子科技有限公司 | A kind of excitation source circuit based on Differential OPAMP |
| CN110838835A (en) * | 2019-11-19 | 2020-02-25 | 天津津航计算技术研究所 | Random signal generating circuit based on high-speed dynamic comparator |
-
2016
- 2016-01-07 CN CN201620014237.XU patent/CN205433689U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107773240A (en) * | 2016-08-24 | 2018-03-09 | 四川锦江电子科技有限公司 | A kind of excitation source circuit based on Differential OPAMP |
| CN110838835A (en) * | 2019-11-19 | 2020-02-25 | 天津津航计算技术研究所 | Random signal generating circuit based on high-speed dynamic comparator |
| CN110838835B (en) * | 2019-11-19 | 2023-04-28 | 天津津航计算技术研究所 | Random signal generating circuit based on high-speed dynamic comparator |
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