CN2857827Y

CN2857827Y - Portable foetus phonocardiograph

Info

Publication number: CN2857827Y
Application number: CNU2005201059634U
Authority: CN
Inventors: (要求不公开姓名)
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-12-23
Filing date: 2005-12-23
Publication date: 2007-01-17
Anticipated expiration: 2015-12-23

Abstract

A portable fetal heart beat monitoring instrument belonging to fetal monitoring domain solves the problem in prior art that everyman can't operating this kind of instruments to do daily monitor since it is difficult to find stethoscopy position. The portable fetal heart beat monitoring instrument includes a sound coupled-cavity 101, an acoustioelectric sensor 102, an analog circuit and a monitoring apparatus 110. The analog circuit includes an analog amplified-filter circuit 103 and a signal AM circuit 108. Comparing with prior art, the disclosed instrument has following advantages: excellent practicability, multifunction, no radiation, no toxicity and side effect, easy operation, simple structure, low cost, small size, light weight, and convenience for carrying.

Description

Portable fetal heart sound monitor

Affiliated technical field:

This utility model relates to fetal monitoring instrument technical field, is specially a kind of portable fetal heart sound monitor.

Background technology:

Whether unusually, in uterus whether the early stage foetus health situation inspection structure of diagnosing fetal effectively have anoxia, symptom such as poverty-stricken, and mother and sons' health, prenatal and postnatal care are had great importance.The Medical Instruments that is used for prefoetal period diagnosis at present all is based on ultrasonic reflection and scanning technique basically, and that specialty requires is high, the instrument price is expensive, is not suitable for domestic or carries, and there is potential injury in fetus.Based on above reason, carried out the research of fetal diagnosis is greatly developed by braking technique, so-called be meant this device not to any energy of human body radiation or ray etc. by braking technique, the signal that utilizes pick off to receive the human fetus passively purely to be produced is monitored and is diagnosed.Three kinds of patterns are arranged in this respect at present, are respectively that chatter signal, bioelectrical signals, the field signal that utilizes heart of fetus to beat to be produced carries out work.Wherein the fetal heart sound auscultation is a kind of tradition and practical method still is being extensive use of so far.Device the earliest is a kind of long and narrow flaring receiver, and an end is attached to doctor's ear, and the other end then is attached to anemia of pregnant woman's abdominal part and monitors.Although experienced the differentiation of nearly two a century, still the principle with original is identical for modern fetal stethoscope, and just receiver and loudspeaker couple together easy to use with rubber tube.Because definition, the audibility of fetal heart sound are poor, and common people lack medical knowledge, especially lack the judgement of fetus at the intravital relative position of mother, it is relatively more difficult usually to seek fetal heartbeat sound, occurred utilizing acoustic-electric conversion mike principle to carry out the electronic machine that fetal heart sound is monitored in recent years on the market, their ultimate principle is to utilize the mike pickoff signals, utilizes simple analog circuit to amplify the back again and is play by earphone.But because people's ear is extremely insensitive to being lower than 100 hertz acoustical signal, this is the one of the main reasons that people are difficult for the identification fetal heart sound.Even if the definition of fetal heart sound is strengthened, if but still be in so low frequency range, common people still are difficult to hear, and are especially all the more so under noisy environment.In addition, earphone is generally relatively poor in the effect of low-frequency range, and frequency response is bad, and output is very low, the identification of more feasible sound to this frequency range difficulty that becomes.Therefore the problem of prior art existence is: do not take effectively noise reduction process, add low frequency, the low signal-to-noise ratio characteristic of fetal heart sound, the ordinary people is difficult to recognize faint fetal heartbeat sound, and the ordinary people can't operate this kind equipment because of searching auscultation position difficulty and carry out daily monitoring.

Summary of the invention:

This utility model will provide a kind of portable fetal heart sound monitor, can't operate the problem that this kind equipment carries out daily monitoring to overcome the ordinary people that prior art exists because of seeking auscultation position difficulty.

For overcoming the problem that prior art exists, the technical solution of the utility model is: a kind of portable fetal heart sound monitor, comprise acoustical coupling chamber 101, acoustoelectric sensor 102, analog circuit and monitoring device 110, comprise simulation amplification filtering circuit 103 and modulation signal circuit 108 in the described analog circuit.

Above-mentioned modulation signal circuit 108 has comprised low-frequency oscillatory network 115 and modulation circuit 116, described low-frequency oscillatory network 115 is by crystal triode T1, resistance R 30, resistance R 31, resistance R 32, resistance R 33, resistance R 34, capacitor C 20, capacitor C 21, capacitor C 22 is formed the phase shift low-frequency oscillatory network, capacitor C 20, capacitor C 21, be connected between the base stage and colelctor electrode of crystal triode T1 after capacitor C 22 series connection, one end of resistance R 30 is with capacitor C 20, the earth point of capacitor C 21 is connected, other end ground connection, one end of resistance R 31 and capacitor C 21, the junction point of capacitor C 22 is connected, other end ground connection, described field effect transistor T2, resistor R 35, resistor R 36 is formed modulation circuit, the output A of simulation amplification filtering circuit 103 is connected with the source electrode of field effect transistor T2 by the coupling capacitance C25 in the modulation circuit, the drain electrode of field effect transistor T2 is the outfan of modulation circuit 116, and this outfan is connected with monitoring device 110.

Above-mentioned modulation circuit 116 is formed the AM single-side-band circuit by increasing high-pass filtering circuit 117, described high-pass filtering circuit 117 is made up of operational amplifier IC3-1 and resistance R 37, resistance R 38, resistance R 39, resistance R 40, resistance R 41, capacitor C 26, capacitor C 27, capacitor C 28, capacitor C 29, the drain electrode of field effect transistor T2 is that the outfan of modulation circuit 116 joins in capacitor C 26 wherein and the modulation signal circuit 108, and the output B of the operational amplifier IC3-1 in the high-pass filtering circuit 117 is connected with monitoring device 110.Amplitude modulation output to suppress carrier frequency and baseband signal, realizes single sideband modulation through high-pass filtering circuit.

Above-mentioned simulation amplification filtering circuit 103 is made of TL072 chip and peripheral typical circuit thereof.

Above-mentioned simulation amplification filtering circuit 103 can also join with gain adjusting circuit 104.

WM034CY type mike, ceramic transducer or film type piezoelectric transducer that above-mentioned acoustoelectric sensor 102 can be Panasonic.

The output of above-mentioned simulation amplification filtering circuit 103 is connected to microprocessor 105, comprise mould/number conversion interface circuit 106, Wiener filtering 107, modulation signal circuit 108 and D/A switch circuit 109 in the microprocessor 105 successively, mould/number conversion interface circuit 106 joins with simulation amplification filtering circuit 103, and the output of D/A switch circuit 109 is connected to monitoring device 110

Also comprise the fetal heart rhythm computing module 111, video interface 112 and the display 114 that connect successively in the above-mentioned microprocessor 105, fetal heart rhythm computing module 111 is connected to mould/number conversion interface circuit 106.

Compared with prior art, the utility model has the advantages that:

1, suitable daily monitoring is used: this utility model is made of analog circuit fully, with pure passive mode work, fetal heart sound definition, audibility height, searching heart of fetus auscultation position are conveniently, practical, being convenient to the layman uses, be that the domestic fetal heart sound that a kind of layman can use is monitored analytical equipment, have simple, cheap, practical advantage.

2, radiationless, have no side effect: because no any ultrasonic radiation, so can be used as long term monitoring, become anemia of pregnant woman, the medical accurately supplementary instrument of a kind of convenience of medical personnel.

3, simple in structure, cost is low: this utility model volume is little, in light weight, be easy to carry, at home, travelling, office all can use.

4, multi-functional: this utility model adopts signal modulation technique to make that hear sounds is easier to be heard, and don't change its beat rhythm and content, the daily domestic so not only suit to carry out, and still can use for the fetal heart sound diagnosis, simultaneously this utility model can add microprocessor, finishes fetal heart rhythm when the user hears comparatively clear loud fetal heart sound and calculates and be presented on the display can making.

Description of drawings:

Below in conjunction with drawings and Examples this utility model is described further.

Fig. 1 is the theory diagram of a kind of embodiment of the present utility model;

Fig. 2 is the circuit theory diagrams of simulation amplification filtering circuit;

Fig. 3 is a kind of embodiment of signal AM single-side-band circuit;

Fig. 4 is the theory diagram of another kind of embodiment of the present utility model.

The specific embodiment:

Below in conjunction with accompanying drawing this utility model is elaborated.

Embodiment 1: referring to Fig. 1～Fig. 3, of the present utility model being constructed as follows: a kind of portable fetal heart sound monitor, comprise acoustical coupling chamber 101, acoustoelectric sensor 102, analog circuit and monitoring device 110, comprise simulation amplification filtering circuit 103 and AM single-side-band circuit 108 in the described analog circuit.Said acoustical coupling chamber 101 is horn-like, and its diameter of dehiscing is that 8cm, base diameter are 0.97cm (with the diameter of the acoustoelectric sensor 102 selected for use), highly are 1cm.Embed acoustoelectric sensor 102 in the loudspeaker bottom, described is to select LF-response mike preferably for use, for example the WM034CY type of Panasonic.

Simulation amplification filtering circuit 103 wherein is made of TL072 chip and peripheral typical circuit thereof.Wherein resistance R 1, resistance R 2, capacitor C 1 are formed the microphone power circuit.Operational amplifier IC1-1, resistance R 3, resistance R 4, resistance R 5, resistance R 6, potentiometer VR1, capacitor C 3 constitute pre-amplifying circuit.Then, by constituting three rank high-pass filtering circuits by operational amplifier IC1-2 and resistance R 7, resistance R 8, resistance R 9, resistance R 10, resistance R 11, capacitor C 5, capacitor C 6, capacitor C 7, three rank low-pass filter circuits by being made of operational amplifier IC2-1, operational amplifier IC2-1 and resistance R 12, resistance R 13, resistance R 14, resistance R 15, resistance R 16, resistance R 17, resistance R 18, resistance R 19, capacitor C 8, capacitor C 9, capacitor C 10 again, output point is A.If cost allows, the part bandwidth-limited circuit also can be chosen high-order filter circuit that the better integrated circuit of performance (for example MAX7400 chip) constitutes and wait and realize.The free transmission range of the band filter that it is combined into is the main frequency component 3 5-110 hertz frequency range of fetal heart sound.

AM single-side-band circuit 108 has wherein comprised low-frequency oscillatory network 115, modulation circuit 116 and high-pass filtering circuit 117.Said low-frequency oscillatory network 115 is by crystal triode T1, resistance R 30, resistance R 31, resistance R 32, resistance R 33, resistance R 34, capacitor C 20, capacitor C 21, capacitor C 22 is formed the phase shift low-frequency oscillatory network, capacitor C 20, capacitor C 21, be connected between the base stage and colelctor electrode of crystal triode T1 after capacitor C 22 series connection, one end of resistance R 30 is with capacitor C 20, the earth point of capacitor C 21 is connected, other end ground connection, one end of resistance R 31 and capacitor C 21, the junction point of capacitor C 22 is connected, other end ground connection, described field effect transistor T2, resistor R 35, resistor R 36 is formed common modulation circuit 116, in modulation circuit 116, increase by operational amplifier IC3-1 and resistance R 37, resistance R 38, resistance R 39, resistance R 40, resistance R 41, capacitor C 26, capacitor C 27, capacitor C 28, the high-pass filtering circuit 117 that capacitor C 29 is formed, just form the single sideband modulated signal modulation circuit, the output A of simulation amplification filtering circuit 103 is connected with the source electrode of field effect transistor T2 by the coupling capacitance C25 in the modulation circuit 116, the drain electrode of field effect transistor T2 is the output terminals A of modulation circuit 116, capacitor C 26 in this outfan and the high-pass filtering circuit 117 is joined, and the output B of the operational amplifier IC3-1 in the high-pass filtering circuit 115 is connected with monitoring device 110.

Carrier frequency does not have strict restriction, can regulate according to actual effect.Consider the audibility after the processing, user's auditory feedback suggestion, suggestion is set in carrier frequency between the 150-250 hertz.

The operation principle of embodiment 1 is: with acoustical coupling chamber 101 uncovered contact anemia of pregnant woman abdominal paries, the acoustic impedance that acoustical coupling chamber 101 is used for carrying out between anemia of pregnant woman's abdominal part sonic vibration and the acoustoelectric sensor 102 mates, and the signal of telecommunication that picks up is amplified with filter circuit 103 by simulation and amplifies and bandpass filtering.Analogue signal input single sideband modulated signal modulation circuit after the processing carries out amplitude modulation to be handled, and audibility is strengthened, and makes the layman also can recognize fetal heart sound at an easy rate.Signal after the processing inserts earphone or speaker 110 is monitored for the user.Entire circuit need not digital-to-analogue conversion, does not have digital operation to handle, but can make the user hear comparatively clear loud fetal heart sound.

Embodiment 2: this utility model and first embodiment similarly part comprise 101, one acoustoelectric sensors in an acoustical coupling chamber 102 and simulation amplification and filter circuit 103.Difference is, through the signal input microprocessor 105 after the analog circuitry processes.Subsequent treatment is carried out with digital form by microprocessor 105 fully, comprises mould/number conversion interface circuit 106, Wiener filtering 107, signal modulation process 108, D/A switch circuit 109, fetal heart rhythm computing module 111, video interface 112 in the microprocessor 105.Mould in the microprocessor 105/number conversion interface circuit 106 is a digital signal 113 with analog signal conversion, and digital signal 113 is at first realized noise reduction process through digital Wiener filtering 107, and then carries out 108 pairs of audibilitys of signal modulation process and strengthen.Digital signal after the processing transfers analogue signal to via D/A switch circuit 109 again, promotes earphone or speaker 110.On the other hand, digital signal 113 also enters fetal heart rhythm computing module 111 to carry out the rhythm of the heart and calculates, and the result is by video interface 112 and be presented on the display 114.

In the present embodiment, mould/number conversion 106 selects lower sample frequency as 2000 hertz even lower, as long as satisfy the requirement of nyquist sampling theorem.

In the present embodiment, adopt the steady background noise in 107 pairs of residual same frequency ranges of digital Wiener filtering to suppress, make definition, the signal to noise ratio of signal obtain bigger raising.Can be observed from waveform, that some are flooded by noise, be difficult for observed hear sounds pulse and all can become very clear.

In the present embodiment, adopt AM single-side-band technology 108, the signal content of whole 35-110 hertz is moved the comparatively frequency range of high frequency, effectively strengthen the audibility of fetal heart sound.Consider the sample frequency of whole digital processing part, the audibility after handling, user's auditory feedback suggestion, suggestion is set in carrier frequency between the 150-250 hertz.In addition, frequency modulation technology also can be applied at this.If signal stronger in the cardiechema signals is modulated to suitable high frequency, and the composition that amplitude is lower is modulated to low frequency, then according to the sensitivity curve of people's ear, people can be easy to big signal of the amplitude of hearing and rhythm thereof, thereby perceive the heart beating of fetus.When reality is used, can take any in these two kinds of methods, also can be used in combination.

Fetal heart rhythm computing module 111 adopts " A rule-basedphonocardiographic method for long-term fetal heart rate monitoring " that the people proposed (IEEE Transaction on Biomedical Engineering such as F.Kovacs, vol.47,2000, pp.124-130) method is carried out fetal heart rhythm calculating.Clinical data shows that the fetal heart sound signal is not only faint, and is mingled with more various disturbing waves, and as inside, abdominal cavity, extraneous bigger sound of movement, anemia of pregnant woman casual touch sensor etc. when measuring, these all can bring difficulty to the calculating of fetal heart frequency.This method can be got rid of interference effectively, makes measurement result reliably accurate.

Microprocessor 105 is realized by a HP iPaq hx4700 hand-held personal digital assistant (PDA).Microprocessor portion also can realize by other multiple modes, is applicable to that example of the present utility model includes but not limited to the distributed computing environment based on microprocessor circuit system, general purpose personal computer, hand-held or laptop devices, programmable consumer electronic device, network PC, telephone system and any said system or equipment.

Though this utility model is described with reference to certain embodiments, the change on any form and the details and the embodiment that do not break away from spirit and scope of the present utility model will be subjected to protection of the present utility model.

Claims

1, a kind of portable fetal heart sound monitor, comprise acoustical coupling chamber (101), acoustoelectric sensor (102), analog circuit and monitoring device (110), it is characterized in that: comprise simulation amplification filtering circuit (103) and modulation signal circuit (108) in the described analog circuit.

2, a kind of portable fetal heart sound monitor as claimed in claim 1, it is characterized in that: described modulation signal circuit (108) has comprised low-frequency oscillatory network (115) and modulation circuit (116), described low-frequency oscillatory network (115) is by crystal triode T1, resistance R 30, resistance R 31, resistance R 32, resistance R 33, resistance R 34, capacitor C 20, capacitor C 21, capacitor C 22 is formed the phase shift low-frequency oscillatory network, capacitor C 20, capacitor C 21, be connected between the base stage and colelctor electrode of crystal triode T1 after capacitor C 22 series connection, one end of resistance R 30 is with capacitor C 20, the earth point of capacitor C 21 is connected, other end ground connection, one end of resistance R 31 and capacitor C 21, the junction point of capacitor C 22 is connected, other end ground connection, described field effect transistor T2, resistor R 35, resistor R 36 is formed modulation circuit, the output A of simulation amplification filtering circuit (103) is connected with the source electrode of field effect transistor T2 by the coupling capacitance C25 in the modulation circuit, the drain electrode of field effect transistor T2 is the outfan of modulation circuit 116, and this outfan is connected with monitoring device (110).

3, a kind of portable fetal heart sound monitor as claimed in claim 2, it is characterized in that: described modulation circuit (116) is formed the single sideband modulated signal modulation circuit by increasing high-pass filtering circuit (117), described high-pass filtering circuit (117) is by operational amplifier IC3-1 and resistance R 37, resistance R 38, resistance R 39, resistance R 40, resistance R 41, capacitor C 26, capacitor C 27, capacitor C 28, capacitor C 29 is formed, the drain electrode of capacitor C 26 wherein and the middle field effect transistor T2 of modulation signal circuit (108) is that the outfan of modulation circuit (116) joins, and the output B of the operational amplifier IC3-1 in the high-pass filtering circuit (117) is connected with monitoring device (110).

4, as claim 1,2 or 3 described a kind of portable fetal heart sound monitors, it is characterized in that: described simulation amplification filtering circuit (103) is made of TL072 chip and peripheral typical circuit thereof.

5, a kind of portable fetal heart sound monitor as claimed in claim 4 is characterized in that: described simulation amplification filtering circuit (103) joins with gain adjusting circuit 104.

6, a kind of portable fetal heart sound monitor as claimed in claim 5 is characterized in that: described acoustoelectric sensor (102) is WM034CY type mike, ceramic transducer or the film type piezoelectric transducer of Panasonic.

7, as claim 1,2 or 3 described a kind of portable fetal heart sound monitors, it is characterized in that: the output of described simulation amplification filtering circuit (103) is connected to microprocessor (105), comprise mould/number conversion interface circuit (106), Wiener filtering (107), modulation signal circuit (108) and D/A switch circuit (109) in the microprocessor (105) successively, mould/number conversion interface circuit (106) joins with simulation amplification filtering circuit (103), and the output of D/A switch circuit (109) is connected to monitoring device (110).

8, a kind of portable fetal heart sound monitor as claimed in claim 7, it is characterized in that: also comprise the fetal heart rhythm computing module (111), video interface (112) and the display (114) that connect successively in the described microprocessor (105), fetal heart rhythm computing module (111) is connected to mould/number conversion interface circuit (106).