CN105147328A - Ultrasonic Doppler fetal heart monitoring system and ultrasonic Doppler fetal heart monitoring method based on stochastic resonance - Google Patents
Ultrasonic Doppler fetal heart monitoring system and ultrasonic Doppler fetal heart monitoring method based on stochastic resonance Download PDFInfo
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- CN105147328A CN105147328A CN201510357122.0A CN201510357122A CN105147328A CN 105147328 A CN105147328 A CN 105147328A CN 201510357122 A CN201510357122 A CN 201510357122A CN 105147328 A CN105147328 A CN 105147328A
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Abstract
The invention relates to an ultrasonic Doppler fetal heart monitoring system and an ultrasonic Doppler fetal heart monitoring method based on stochastic resonance. The system comprises an ultrasonic receiver, a band-pass filter, a demodulation and detection device, an absolute-value circuit and a stochastic resonance circuit, wherein the ultrasonic receiver is used for receiving ultrasonic echo signals and noise signals; the ultrasonic echo signals are formed according to periodic fetal heart rate signals; the band-pass filter is used for selecting the echo signals with ultrasonic carrier frequency; the demodulation and detection device is used for separating low-frequency modulating signals from high-frequency carrier signals in a product result of the echo signals and local oscillator carrier signals; the absolute-value circuit is used for acquiring envelope signals comprising fetal heart rate in the low-frequency modulating signals; and the stochastic resonance circuit is used for acquiring periodic fetal heart rate signals in the envelope signals. By the stochastic resonance circuit, the fetal heart rate envelope signals in noises can be detected, and the ultrasonic Doppler fetal heart monitoring system is low in radiation quantity and high in sensitivity.
Description
Technical field
The present invention relates to technical field of medical detection, particularly relate to a kind of ultrasonic doppler fetal rhythm monitoring system based on accidental resonance and method.
Background technology
In mother's intrauterine and birth process, problems such as fetus transient ischemic, anoxia and the fetal malnutrition that causes, growth retardation, fetal distress may being caused, even suffocate, be dead.A large amount of clinical proof, Fetal heart electronic monitor effectively can find the exception of fetus in During Pregnancy, has very important clinical meaning.Therefore, accurately the instantaneous heart rate of fetus is calculated in real time for judging that the health status of fetus in parent is extremely important.Under normal circumstances, fetal heart rate signal can pass through ultrasonic doppler, bioelectrode and mike and obtain, wherein Ultrasound Doppler Method has the advantages that precision is high, capacity of resisting disturbance is strong, versatility is good, be easy to realization, is widely used, such as Doppler's fetal heart detector.
On the one hand, fetal rhythm volume is little, motion amplitude displacement is weak and the sensitivity of Doppler's fetal heart detector not enough, affects the monitoring to early stage pregnant all fetuses, easily causes flase drop; Detecting certainty of measurement for improving fetal rhythm, needing to improve ultrasonic radiation dosage.On the other hand, flase drop situation can be reduced by increasing ultrasonic radiation dosage, but radiation dose is excessive, can affect the nervous system of fetus and the growth promoter of brain; Need to reduce ultrasonic radiation dosage for reducing the physiological effect of ultrasonic radiation to fetus.Like this, sensitivity and radiation dose just define contradiction.
For Ultrasonic Radiation dosage to the influential worry of fetus, doctor constantly can turn down the transmitting power of sensing transducer, even can lower than Medical Instruments standard.This way is fixing safer, but the reflection echo gathered also can be fainter, proposes new demand to the sensitivity of testing circuit.
Summary of the invention
For defect of the prior art, the invention provides a kind of ultrasonic doppler fetal rhythm monitoring system based on accidental resonance and method, the fetal rhythm heart rate detection in Low emissivity amount situation can be realized.
First aspect, the present invention proposes a kind of ultrasonic doppler fetal rhythm monitoring system based on accidental resonance, comprising:
Ultrasonic receiver, for receiving the ultrasonic echo signal and noise signal that are formed according to cycle fetal rhythm heart rate signal;
Band filter, for selecting the echo-signal of ultrasonic carrier frequency;
Demodulation cymoscope, for separating of the low-frequency modulation signal in the result of product of described echo-signal and local oscillator carrier signal and high-frequency carrier signal;
Absolute value circuit, comprises the envelope signal of fetal rhythm heart rate for obtaining described low-frequency modulation signal;
Also comprise:
Accidental resonance circuit, for obtaining the cycle fetal rhythm heart rate signal in described envelope signal.
Alternatively, described accidental resonance circuit comprises summation electronic circuit, integration electronic circuit and feedback circuit, and wherein, described summation electronic circuit comprises the first operational amplifier and the second amplifier to described summation electronic circuit;
The inverting input of described first operational amplifier obtains fetal rhythm heart rate signal by the first resistance, and obtains noise by the second resistance; Normal phase input end connects predeterminated voltage by the 3rd resistance; Outfan is electrically connected with the inverting input of described second amplifier by the 5th resistance; Outfan is electrically connected with inverting input by the 4th resistance;
The normal phase input end of described second amplifier connects predeterminated voltage by the 6th resistance, and outfan is electrically connected with inverting input by the 7th resistance.
Alternatively, described integration electronic circuit comprises the 3rd operational amplifier, the inverting input of described 3rd operational amplifier and the outfan of described first accidental resonance electronic circuit, normal phase input end connects predeterminated voltage by the 9th resistance, and outfan is connected with inverting input by electric capacity;
Second end of described second multiplier is connected to the outfan of described 3rd operational amplifier, and the 3rd end is connected predeterminated voltage via the first end of the second adjustable resistance with the second end; 3rd end of described the second adjustable resistance connects the inverting input of the 3rd operational amplifier by the 13 resistance.
Alternatively, described feedback circuit comprises four-operational amplifier, the normal phase input end of described four-operational amplifier connects predeterminated voltage by resistance, inverting input is connected with the outfan of operational amplifier by the tenth resistance, outfan is connected predeterminated voltage via the first variable-resistance first end with the second end, and outfan is connected with inverting input by the 12 resistance; Described first variable-resistance 3rd end connects the inverting input of the 3rd operational amplifier by the 12 resistance;
The first end of described first multiplier and the second end are connected to the outfan of described four-operational amplifier, and three-terminal link is to the first end of described second multiplier.
Alternatively, described monitoring system also comprises pulse shaper, and it is digit pulse square-wave signal that described pulse shaper is used for cycle fetal rhythm heart rate signal described in shaping.
Alternatively, described monitoring system also comprises microprocessor, and described microprocessor obtains fetal rhythm heart rate for the frequency detecting described data pulse square-wave signal.
Alternatively, described monitoring system also comprises low pass filter, and described low-energy filter is arranged between described demodulation detector and described absolute value circuit, for high-frequency carrier signal described in filtering.
Alternatively, described monitoring system also comprises audio frequency amplifier, and described audio frequency amplifier is for amplifying described low-frequency modulation signal.
Second aspect, invention further provides a kind of ultrasonic doppler fetal rhythm monitoring method based on accidental resonance, it is characterized in that, comprising:
Ultrasonic receiver receives the ultrasonic echo signal and noise signal that are formed according to fetal rhythm heart rate signal;
The echo-signal of ultrasonic carrier frequency selected by band filter;
Demodulation cymoscope is separated low-frequency modulation signal in the result of product of described echo-signal and local oscillator carrier signal and high-frequency carrier signal;
Absolute value circuit obtains the envelope signal that described low-frequency modulation signal comprises fetal rhythm heart rate;
Accidental resonance circuit obtains the fetal rhythm heart rate signal in described envelope signal.
Alternatively, described accidental resonance circuit obtains the fetal rhythm heart rate signal in described envelope signal, adopts following calculating formula:
Wherein, a and b is the system of bistable system model, and s (t) is for comprising the cycle fetal rhythm heart rate signal of noise, s (t)=Acos (ω
0t)+Γ (t), Γ (t) are noise figure, Acos (ω
0t) be cycle fetal rhythm heart rate signal.
The present invention is by arranging accidental resonance circuit, and detected by the fetal rhythm heart rate envelope signal be mixed in noise, amount of radiation is few, highly sensitive.
Accompanying drawing explanation
Can understanding the features and advantages of the present invention clearly by reference to accompanying drawing, accompanying drawing is schematic and should not be construed as and carry out any restriction to the present invention, in the accompanying drawings:
Fig. 1 is ultrasonic doppler fetal rhythm monitoring system block diagram provided by the invention;
Fig. 2 is the circuit theory diagrams of band filter provided by the invention;
Fig. 3 is that local oscillation signal provided by the invention produces circuit theory diagrams;
Fig. 4 is the circuit theory diagrams of demodulation cymoscope provided by the invention;
Fig. 5 is the circuit theory diagrams of low pass filter provided by the invention;
Fig. 6 is the circuit theory diagrams of absolute value circuit provided by the invention;
Fig. 7 is the circuit theory diagrams of low pass filter provided by the invention;
Fig. 8 is accidental resonance circuit theory diagrams provided by the invention;
Fig. 9 is the kinetics equation data flowchart of accidental resonance circuit provided by the invention;
Figure 10 is the input/output signal design sketch of the accidental resonance circuit that Fig. 9 provides;
Figure 11 is pulse shaper schematic diagram provided by the invention;
Figure 12 is the functional schematic block diagram of microprocessor provided by the invention;
Figure 13 is the ultrasonic power amplifier module schematic diagram of Low emissivity amount provided by the invention.
Detailed description of the invention
For making the object of the embodiment of the present invention, technical scheme and advantage clearly, below in conjunction with the accompanying drawing in the embodiment of the present invention, technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to the scope of protection of the invention.
First aspect, the present invention proposes a kind of ultrasonic doppler fetal rhythm monitoring system based on accidental resonance, as shown in Figure 1, comprising:
Ultrasonic receiver, for receiving the ultrasonic echo signal and noise signal that are formed according to cycle fetal rhythm heart rate signal;
Band filter, for selecting the echo-signal of ultrasonic carrier frequency;
Demodulation cymoscope, for separating of the low-frequency modulation signal in the result of product of described echo-signal and local oscillator carrier signal and high-frequency carrier signal;
Absolute value circuit, comprises the envelope signal of fetal rhythm heart rate for obtaining low-frequency modulation signal;
Also comprise:
Accidental resonance circuit, for obtaining the cycle fetal rhythm heart rate signal in envelope signal.
Periodic signal, by adopting two-stage circuit, detects by the present invention from noise, thus realizes when low radiation dose, detects fetal rhythm heart rate.
As shown in Figure 1, the ultrasonic signal launched of ultrasound emission transducer.Ultrasonic signal waveform is:
V
cw＝sin(ωt)(1)
V
cwfor ultrasonic emitting signal voltage, ω are angular frequency;
Ultrasonic transducer receives the ultrasonic echo signal and noise signal that are formed according to fetal rhythm heart rate.Echo-signal is secondary wave, symbolization V
secrepresent, it is the function of signal angular frequency, signal amplitude A, angle phi.Compare and transmitted wave V
cwecho-signal V
secamplitude A
secall there occurs change with phase, available mathematical description is:
V
sec(ω,A,φ)＝A
secsin(ωt+φ)(2)
And by this ultrasonic echo signal and noise signal transmission to band filter.Above-mentioned ultrasonic echo signal and noise signal are carried out filtering by band filter, and permission carrier frequency is that the signal of ultrasonic frequency passes through.
Fig. 2 shows the circuit theory diagrams of band filter, and circuit structure is as follows: resistance R32, resistance R33, resistance R34 connect, and one end of the plurality of resistance connects predeterminated voltage, and the other end connects voltage VCC.The junction point place of resistance R32 and resistance R33 is connected at the grid of transistor Q1, form the bias voltage of transistor Q1, source electrode is connected to the junction point place of resistance R33 and resistance R34, and the antiresonant circuit formed by resistance R31 and electric capacity C35 that drains is connected to predeterminated voltage.Input signal is connected to the junction point place of resistance R32 and resistance R33 by electric capacity C34.Inductance L 1 and electric capacity C31 form series resonant circuit and are exported by the signal at the junction point place of resistance R33 and resistance R34.By selecting suitable resistance and capacitance, and regulate the operating point of transistor Q1, this band filter amplifies and frequency-selective filtering the carrying out being loaded with fetal heart rate signal received.
As shown in Figure 3, local oscillation signal produces circuit: in parallel with phase inverter U5A after crystal oscillator X1 connects with resistance R41, and resistance R43 is also in parallel with phase inverter U5A simultaneously.It is in parallel with crystal oscillator X1 after electric capacity C41 and C42 connects.Phase inverter U6A, U2A, U9A are connected with the outfan of phase inverter U5A with after the first end parallel connection of U3A.Wherein, second end of phase inverter U9A, U3A is connected, and second end of phase inverter U6A, U2A is connected and outputting oscillation signal.
Present invention also offers a kind of demodulation cymoscope.The fetal rhythm doppler shifted signal demodulation that this demodulation cymoscope realizes band filter exports detects.Signal by band filter is multiplied with local oscillator carrier signal, isolates low-frequency modulation signal and high-frequency carrier signal.
In theory, the modulation signal that echo-signal obtains after low-pass filtering is:
When an object is moving, can there is frequency difference Δ f in echo-signal and carrier signal:
In formula, v is target speed, and c is the transonic velocity of sound, and f is carrier frequency.Frequency difference size delta f and radial target motion velocity component value linear.V
rphase information φ in signal is consistent with Δ f.By detecting sequence V
rin dominant frequency components can obtain Δ f.Be detected change and the signal V of target speed v simultaneously
rin amplitude information A
secunanimously.
Wherein, low-frequency modulation signal is useful signal, is loaded with fetal rhythm doppler shifted signal and fetal rhythm heart rate envelope signal.Therefore, this demodulation cymoscope achieves Doppler signal and moves to low frequency.
Fig. 4 shows and embodiments provides a kind of demodulation cymoscope.As shown in Figure 5, connect after electric capacity C52 and electric capacity C53 parallel connection with resistance R51, the first end of the series circuit formed connects voltage VCC, and the second end connects predeterminated voltage.At the intersection point of resistance R51 and electric capacity C52 and electric capacity C parallel circuit respectively by the pin CIN+ of resistance R54 connecting analog multiplier MC1496D, pin CIN-, the resistance R52 of resistance R53 connecting analog multiplier MC1496D is connected pin SIGIN and resistance R55 connects pin BIAR.Echo-signal positive pole, negative pole are connected to pin SIGIN+, the pin SIGIN of analog multiplier MC1496D respectively.Local oscillation signal is by the pin CIN-of electric capacity C54 connecting analog multiplier MC1496D.
As shown in Figure 4, the pin 2 of analog multiplier MC1496D is connected with pin 3 by resistance R56, and pin VEE connects predeterminated voltage; The inverting input of concatenation operation amplifier U2A after pin OUT+ connects with electric capacity C58, resistance R510.Be connected voltage VCC, connect predeterminated voltage by electric capacity C55 with the junction point place of electric capacity C58 respectively by resistance R58 at pin OUT+.The normal phase input end of concatenation operation amplifier U2A after the pin OUT of analog multiplier MC1496D connects with electric capacity C57, resistance R511; Be connected voltage VCC, connect predeterminated voltage by electric capacity C56 with electric capacity C57 junction point respectively by resistance R59 at pin OUT; Predeterminated voltage is connected with the junction point place of operational amplifier U2A by resistance R512 at resistance R511.
Also have resistance R513 at the outfan of operational amplifier U2A and inverting input, the outfan of this operational amplifier U2A exports restituted signal.
Alternatively, monitoring system also comprises low pass filter, and low-energy filter is arranged between demodulation detector and absolute value circuit, for filtering high-frequency carrier signal.
Fig. 5 shows the circuit of the low pass filter that the embodiment of the present invention provides, for exporting the signal being loaded with fetal rhythm Doppler shift information and fetal rhythm heart rate envelope information.As shown in Figure 6, the signal exported by demodulation detector is connected with the normal phase input end of operational amplifier U63A by resistance R61, and the junction point of resistance R61 and normal phase input end connects predeterminated voltage by electric capacity R61.The inverting input of operational amplifier U63A is connected with outfan.The outfan of operational amplifier U63A outputs signal audio amplifier circuit and buzzer, absolute value circuit.
Fig. 6 shows a kind of absolute value circuit that the embodiment of the present invention provides.Absolute value circuit output signal comprises fetal rhythm doppler shifted signal and fetal rhythm heart rate envelope signal.
As shown in Figure 6, enter the inverting input of operational amplifier U71A through resistance R71 from the signal of low pass filter.The inverting input of this operational amplifier U71A connect with resistance R72, R74 after the normal phase input end of concatenation operation amplifier U72A, the inverting input of the concatenation operation amplifier U72A afterwards of connecting with resistance R73, R75.The normal phase input end of operational amplifier U71A connects predeterminated voltage; Power cathode connects 5V voltage, and connects predeterminated voltage by electric capacity C71, and positive source connects 5V voltage, and connects predeterminated voltage by electric capacity C72.Diode D71 and D72 connects, and wherein, the positive pole of diode D72 is connected to the junction point place of resistance R73 and resistance R75, and the negative pole of diode D71 is connected to the junction point place of resistance R72 and resistance R74.The outfan of operational amplifier U71A is connected to the junction point place of diode D71 and D72.In addition, between the inverting input and outfan of operational amplifier U72A, resistance R76 is also provided with.
Fig. 7 shows a kind of low-pass filter circuit that the embodiment of the present invention provides, because fetal rhythm heart rate envelope information is for fetal rhythm Doppler shift information, belong to high-frequency information, that selects the low pass filter of band connection frequency between 0.2Hz-4Hz fetal rhythm heart rate envelope information can be completed extract, and place to go Doppler frequency shift high fdrequency component.As shown in Figure 7, from the signal of low pass filter by entering the inverting input of operational amplifier U81A after electric capacity C80, resistance R81 and electric capacity C82.Predeterminated voltage is connected by resistance R82 on the one hand with the junction point place of electric capacity C82, on the other hand by the outfan of electric capacity C81 concatenation operation amplifier U81A at resistance R81.Resistance R83 is also provided with between the inverting input of operational amplifier U81A and outfan.The normal phase input end of operational amplifier U81A connects predeterminated voltage, and its power cathode connects-5V voltage, and connects predeterminated voltage by electric capacity C84; Positive source connects+5V voltage, and connects predeterminated voltage by electric capacity C83; Outfan is by the inverting input of resistance R84, electric capacity C86 concatenation operation amplifier U82A.
At the junction point place of resistance R84 and electric capacity C86, access predeterminated voltage by resistance R85 on the one hand, on the other hand by the outfan of electric capacity C85 concatenation operation amplifier U82A.Between the outfan and normal phase input end of operational amplifier U82A, be also provided with resistance R86, and by electric capacity C87, signal exported.
Low-pass filter output signal is fetal rhythm heart rate envelope information, frequency range between 0.2Hz-4Hz, namely between 30 times to 240 times per minute.Generally speaking, under the ultrasonic radiation condition of low dosage, low-pass filter output signal comprises much noise, and wherein, traditional detection method is difficult to effectively detect the disappearance of fetal rhythm heart rate envelope information.This is also the key point of constraint fetal heart detector device performance.Consider that fetal rhythm heart rate envelope information is cyclical signal.For this reason, a kind of accidental resonance circuit of providing of the embodiment of the present invention.
Alternatively, accidental resonance circuit comprises summation electronic circuit, integration electronic circuit and feedback circuit, and wherein, summation electronic circuit comprises the first operational amplifier and the second amplifier to summation electronic circuit.
In practical application, as shown in Figure 8, electronic circuit of suing for peace comprises operational amplifier 1, operational amplifier 2.The inverting input of operational amplifier 1 is respectively by resistance R1, resistance R2 connection signal, noise; Normal phase input end connects predeterminated voltage by resistance R4; Resistance R3 is provided with between the inverting input and output of operational amplifier 1; And, the outfan of operational amplifier 1 is connected with the inverting input of operational amplifier 2 by resistance R5, normal phase input end connects predeterminated voltage by resistance R6, between the inverting input and outfan of operational amplifier 2, be provided with resistance R7, and outfan is connected with the second accidental resonance electronic circuit.
Integration electronic circuit comprises operational amplifier 3 and multiplier 2.Wherein, operational amplifier 3 inverting input is connected with the outfan of operational amplifier 2 by resistance R8; Inverting input connects predeterminated voltage by resistance R9, between inverting input and outfan, be also provided with electric capacity C.The outfan of another input concatenation operation amplifier 3 of multiplier 2, outfan connects predeterminated voltage by variable resistance K2.The adjustable end of variable resistance K2 is connected with the inverting input of operational amplifier 3 by resistance R14.
Feedback sub-circuit comprises operational amplifier 4 and multiplier 1.The inverting input of operational amplifier 4 is connected with the outfan of operational amplifier 3 by resistance R10, and normal phase input end connects predeterminated voltage by resistance R12, is provided with resistance R11 between inverting input and outfan; Outfan connects predeterminated voltage by variable resistance K1.The adjustable end of variable resistance K1 is connected with the inverting input of operational amplifier 3 by resistance R13.The outfan of two input concatenation operation amplifiers 4 of multiplier 1, outfan connects an input of multiplier 2.
The accidental resonance circuit that the embodiment of the present invention provides is for extracting in the environment of Arctic ice area periodic signal, and phase information is almost constant.Its principle is as follows, and its kinetics equation is as follows:
Wherein, a and b is the system of bistable system model, and s (t) is for comprising the cycle fetal rhythm heart rate signal of noise, s (t)=Acos (ω
0t)+Γ (t), Γ (t) are noise figure, Acos (ω
0t) be cycle fetal rhythm heart rate signal.
As shown in Figure 9, differential signal ddxt obtains signal x after integrator.On the one hand, this signal x obtains signal ax and outputs in summing circuit after multiplier; On the other hand, this signal x obtains signal x after repeatedly multiplication
3, signal x
3signal-bx is obtained after multiplier-b
3, and should number-bx
3deliver in summing circuit.Weak periodic signal and noise signal also input to summing circuit.By detection signal x, weak periodic signal can be obtained, i.e. cycle fetal rhythm heart rate signal.
As shown in Figure 10, the Input Monitor Connector signal comprising noise has been shown in Figure 10 (a), Figure 10 (b) shows the signal after accidental resonance processing of circuit, can find, the embodiment of the present invention has good noise suppression effect, achieves the extraction that fetal rhythm envelope signal is cyclical signal.
The waveform that Figure 10 (b) illustrates also needs further process, and the embodiment of the present invention additionally provides pulse shaper for this reason.As shown in figure 11, this pulse shaper structure is as follows: signal enters the normal phase input end of operational amplifier U121A by resistance R121.The first end of variable resistance R122 connects+5V voltage, and the second end connects predeterminated voltage, the inverting input of three-terminal link operational amplifier U121A.The positive pole of electric capacity C121 connects+5V voltage, and negative pole end connects predeterminated voltage.The positive source of operational amplifier connects+5V voltage, power cathode exports signal to microcontroller after connecting predeterminated voltage, outfan contact resistance R123.
As shown in figure 12, the microprocessor that the embodiment of the present invention provides comprises auxiliary IP administration module, pulse signal detection module, task management module and number and passes display control module.Wherein, the square-wave signal that pulse signal detection module provides for paired pulses circuit carries out frequency detecting; Task management module is responsible for the scheduling between each real-time task; Number passes display control module and is responsible for man-machine interaction, network data transmission etc.; Auxiliary IP administration module is responsible for the management of the online signal such as button, relay indicating light.This part content can adopt existing techniques in realizing, and the present invention is not construed as limiting.
Present invention also offers the ultrasonic power amplifier module of a kind of Low emissivity amount.As shown in figure 13, input signal Si ngna_IN connects the base stage of transistor Q141 through resistance R141, and the emitter stage of this transistor Q141 also connects predeterminated voltage by resistance R142.The colelctor electrode of this transistor Q141 connects predeterminated voltage respectively through electric capacity C141, inductance L 142 be connected voltage VCC after R145, be connected predeterminated voltage through inductance L 141, electric capacity C142 after resistance R144, and output signal through the junction point place of electric capacity C142 and resistance R144.
Monitor fetal heart sound for the ease of doctor, the present invention can also increase audio amplifier circuit.This audio amplifier circuit can adopt existing techniques in realizing, and the present invention is not construed as limiting.
In practical application, the predeterminated voltage described in the present invention is signal or data earth signal in analog, and those skilled in the art can select as the case may be, and the present invention is not construed as limiting.
In practical application, ultrasonic receiver provided by the invention, band filter, demodulation cymoscope, absolute value circuit and accidental resonance circuit also can adopt other circuit realiration, and the present invention is not construed as limiting.
Second aspect, invention further provides a kind of ultrasonic doppler fetal rhythm monitoring method based on accidental resonance, comprising:
Ultrasonic receiver receives the ultrasonic echo signal and noise signal that are formed according to fetal rhythm heart rate signal;
The echo-signal of ultrasonic carrier frequency selected by band filter;
Demodulation cymoscope is separated low-frequency modulation signal in the result of product of described echo-signal and local oscillator carrier signal and high-frequency carrier signal;
Absolute value circuit obtains the envelope signal that described low-frequency modulation signal comprises fetal rhythm heart rate;
Accidental resonance circuit obtains the fetal rhythm heart rate signal in described envelope signal.
Alternatively, described accidental resonance circuit obtains the fetal rhythm heart rate signal in described envelope signal, adopts following calculating formula:
Wherein, a and b is the system of bistable system model, and s (t) is for comprising the cycle fetal rhythm heart rate signal of noise, s (t)=Acos (ω
0t)+Γ (t), Γ (t) are noise figure, Acos (ω
0t) be cycle fetal rhythm heart rate signal.
Accidental resonance circuit can when the signal to noise ratio of s (t) is minimum (<<-10dB) by periodic signal Acos (ω
0t) detect.
Because ultrasonic doppler fetal rhythm monitoring method and system realize based on same inventive concept, have same technique effect, this is no longer going to repeat them.
It should be noted that in describing the invention, term " on ", the orientation of the instruction such as D score or position relationship be based on orientation shown in the drawings or position relationship, only the present invention for convenience of description and simplified characterization, instead of indicate or imply that the device of indication or element must have specific orientation, with specific azimuth configuration and operation, therefore can not be interpreted as limitation of the present invention.Unless otherwise clearly defined and limited, term " installation ", " being connected ", " connection " should be interpreted broadly, and such as, can be fixedly connected with, also can be removably connect, or connect integratedly; Can be mechanical connection, also can be electrical connection; Can be directly be connected, also indirectly can be connected by intermediary, can be the connection of two element internals.For the ordinary skill in the art, above-mentioned term concrete meaning in the present invention can be understood as the case may be.
Also it should be noted that, in this article, the such as relational terms of first and second grades and so on is only used for an entity or operation to separate with another entity or operating space, and not necessarily requires or imply the relation that there is any this reality between these entities or operation or sequentially.And, term " comprises ", " comprising " or its any other variant are intended to contain comprising of nonexcludability, thus make to comprise the process of a series of key element, method, article or equipment and not only comprise those key elements, but also comprise other key elements clearly do not listed, or also comprise by the intrinsic key element of this process, method, article or equipment.When not more restrictions, the key element limited by statement " comprising ... ", and be not precluded within process, method, article or the equipment comprising described key element and also there is other identical element.
Above embodiment only in order to technical scheme of the present invention to be described, is not intended to limit; Although with reference to previous embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that: it still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein portion of techniques feature; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the spirit and scope of various embodiments of the present invention technical scheme.
Claims (10)
1., based on a ultrasonic doppler fetal rhythm monitoring system for accidental resonance, it is characterized in that, comprising:
Ultrasonic receiver, for receiving the ultrasonic echo signal and noise signal that are formed according to cycle fetal rhythm heart rate signal;
Band filter, for selecting the echo-signal of ultrasonic carrier frequency;
Demodulation cymoscope, for separating of the low-frequency modulation signal in the result of product of described echo-signal and local oscillator carrier signal and high-frequency carrier signal;
Absolute value circuit, comprises the envelope signal of fetal rhythm heart rate for obtaining described low-frequency modulation signal;
Also comprise:
Accidental resonance circuit, for obtaining the cycle fetal rhythm heart rate signal in described envelope signal.
2. ultrasonic doppler fetal rhythm monitoring system as claimed in claim 1, is characterized in that,
Described accidental resonance circuit comprises summation electronic circuit, integration electronic circuit and feedback circuit, and wherein, described summation electronic circuit comprises the first operational amplifier and the second amplifier to described summation electronic circuit;
The inverting input of described first operational amplifier obtains fetal rhythm heart rate signal by the first resistance, and obtains noise by the second resistance; Normal phase input end connects predeterminated voltage by the 3rd resistance; Outfan is electrically connected with the inverting input of described second amplifier by the 5th resistance; Outfan is electrically connected with inverting input by the 4th resistance;
The normal phase input end of described second amplifier connects predeterminated voltage by the 6th resistance, and outfan is electrically connected with inverting input by the 7th resistance.
3. ultrasonic doppler fetal rhythm monitoring system as claimed in claim 2, is characterized in that,
Described integration electronic circuit comprises the 3rd operational amplifier, the inverting input of described 3rd operational amplifier and the outfan of described first accidental resonance electronic circuit, normal phase input end connects predeterminated voltage by the 9th resistance, and outfan is connected with inverting input by electric capacity;
Second end of described second multiplier is connected to the outfan of described 3rd operational amplifier, and the 3rd end is connected predeterminated voltage via the first end of the second adjustable resistance with the second end; 3rd end of described the second adjustable resistance connects the inverting input of the 3rd operational amplifier by the 13 resistance.
4. ultrasonic doppler fetal rhythm monitoring system as claimed in claim 2, is characterized in that,
Described feedback circuit comprises four-operational amplifier, the normal phase input end of described four-operational amplifier connects predeterminated voltage by resistance, inverting input is connected with the outfan of operational amplifier by the tenth resistance, outfan is connected predeterminated voltage via the first variable-resistance first end with the second end, and outfan is connected with inverting input by the 12 resistance; Described first variable-resistance 3rd end connects the inverting input of the 3rd operational amplifier by the 12 resistance;
The first end of described first multiplier and the second end are connected to the outfan of described four-operational amplifier, and three-terminal link is to the first end of described second multiplier.
5. ultrasonic doppler fetal rhythm monitoring system as claimed in claim 1, is characterized in that,
Described monitoring system also comprises pulse shaper, and it is digit pulse square-wave signal that described pulse shaper is used for cycle fetal rhythm heart rate signal described in shaping.
6. ultrasonic doppler fetal rhythm monitoring system as claimed in claim 5, is characterized in that,
Described monitoring system also comprises microprocessor, and described microprocessor obtains fetal rhythm heart rate for the frequency detecting described data pulse square-wave signal.
7. ultrasonic doppler fetal rhythm monitoring system as claimed in claim 1, is characterized in that,
Described monitoring system also comprises low pass filter, and described low-energy filter is arranged between described demodulation detector and described absolute value circuit, for high-frequency carrier signal described in filtering.
8. ultrasonic doppler fetal rhythm monitoring system as claimed in claim 1, is characterized in that,
Described monitoring system also comprises audio frequency amplifier, and described audio frequency amplifier is for amplifying described low-frequency modulation signal.
9., based on a ultrasonic doppler fetal rhythm monitoring method for accidental resonance, it is characterized in that, comprising:
Ultrasonic receiver receives the ultrasonic echo signal and noise signal that are formed according to fetal rhythm heart rate signal;
The echo-signal of ultrasonic carrier frequency selected by band filter;
Demodulation cymoscope is separated low-frequency modulation signal in the result of product of described echo-signal and local oscillator carrier signal and high-frequency carrier signal;
Absolute value circuit obtains the envelope signal that described low-frequency modulation signal comprises fetal rhythm heart rate;
Accidental resonance circuit obtains the fetal rhythm heart rate signal in described envelope signal.
10. ultrasonic doppler fetal rhythm monitoring method as claimed in claim 9, is characterized in that,
Described accidental resonance circuit obtains the fetal rhythm heart rate signal in described envelope signal, adopts following calculating formula:
Wherein, a and b is the system of bistable system model, and s (t) is for comprising the cycle fetal rhythm heart rate signal of noise, s (t)=Acos (ω
0t)+Γ (t), Γ (t) are noise figure, Acos (ω
0t) be cycle fetal rhythm heart rate signal.
Priority Applications (1)
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|---|---|---|---|
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| CN109009234A (en) * | 2018-05-25 | 2018-12-18 | 上海夏先机电科技发展有限公司 | A method of it is practised contraception based on user information, easily pregnant, excellent pregnant evaluation |
| CN111308465A (en) * | 2020-03-26 | 2020-06-19 | 中国气象局气象探测中心 | Method for identifying airborne creatures based on Doppler velocity and azimuth filtering |
| CN111759354A (en) * | 2020-07-23 | 2020-10-13 | 广州互云医院管理有限公司 | Ultrasonic fetal heart monitoring device |
| CN113974282A (en) * | 2021-11-30 | 2022-01-28 | 中国人民解放军陆军军医大学士官学校附属医院 | A intelligent bracelet for monitoring pregnant woman's sign |
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