CN106388808B

CN106388808B - Novel multichannel electrocardiogram acquisition scheme

Info

Publication number: CN106388808B
Application number: CN201510366092.XA
Authority: CN
Inventors: 席剑
Original assignee: Guangzhou 3ray Electronics Co ltd
Current assignee: Guangzhou 3ray Electronics Co ltd
Priority date: 2015-06-26
Filing date: 2015-06-26
Publication date: 2021-05-25
Anticipated expiration: 2035-06-26
Also published as: CN106388808A

Abstract

The invention discloses a novel multichannel electrocardiogram acquisition scheme, which comprises an electrocardiogram amplification circuit, a multi-path analog-to-digital converter and a related digital signal processing algorithm. The electrocardiogram amplifier is characterized in that each channel of the electrocardiogram amplifier circuit can simultaneously complete the buffering amplification and the differential amplification of the electrocardiogram by using a single operational amplifier, and chest leads do not need Wilson central potential; the output of the ECG amplifying circuit is synchronously sampled by a multi-channel analog-to-digital converter to form digital signals, and standard ECG leads are calculated by a related digital signal processing algorithm. By adopting the novel electrocardiogram acquisition scheme, the electrocardiogram amplification circuit is greatly simplified, the production cost can be obviously reduced, and the signal-to-noise ratio of the electrocardiogram waveform is also improved.

Description

Novel multichannel electrocardiogram acquisition scheme

[ technical field ] A method for producing a semiconductor device

The invention relates to a novel multichannel electrocardiogram acquisition scheme, which comprises an electrocardiogram amplification circuit and a digital signal processing algorithm.

[ background of the invention ]

The electrocardiograph is a non-invasive and cheap physiological function detecting instrument for recording the heart electrical activity waveform (namely, electrocardiogram), can provide basic information for diagnosing and treating various heart diseases, is helpful for analyzing various arrhythmia, and understanding the influence of certain drugs and electrolyte disturbance and acid-base imbalance on cardiac muscle, and has an important position in routine examination of heart diseases. The electrocardiograph commonly used in clinic records a standard twelve-lead electrocardiogram by means of four limb electrodes (L left limb electrode, R right limb electrode, F left leg electrode, RF right leg electrode) and six chest electrodes (C1/C2/C3/C4/C5/C6) placed on the body surface. The name classification and calculation formula of the twelve leads are shown in the following table:

TABLE 1 name Classification and calculation formula for conventional twelve leads

The twelve-lead digital electrocardiographs currently on the market basically adopt a digital signal processing technology, and only eight-lead electrocardiograms (I, II, V1, V2, V3, V4, V5 and V6) need to be sampled synchronously, and other leads are calculated according to the formula (III-II-I; aVR-II/2-I/2; aVL-I-II/2; aVF-II-I/2). Since all chest leads (V1, V2, V3, V4, V5, V6) are associated with (L + R + F)/3, here (L + R + F)/3 is referred to as the Wilson center potential.

Because the body surface electrocardiogram signal amplitude is small (about 1mVp-p), the internal resistance is large (about 51K omega capacitive impedance) and □ is accompanied by strong common-mode interference (about 1Vp-p) introduced by an alternating current power grid, the electrocardiogram acquisition circuit adopting the traditional scheme needs to adopt two-stage precise amplification circuits: the first stage buffer amplifier circuit (high input impedance) synthesizes Wilson center potential at the same time, the second stage differential amplifier circuit (high common mode rejection ratio) eliminates common mode interference, eight electrocardiogram leads (I, II, V1, V2, V3, V4, V5 and V6) are generated, and the signals are supplied to the analog-to-digital conversion circuit and the Central Processing Unit (CPU) of the later stage for digital signal processing.

Besides the twelve-lead electrocardiograph, the electrocardiograph acquisition scheme is also applied to an electrocardiograph monitor, a fifteen/sixteen/eighteen-lead electrocardiograph and the like, the electrocardiograph applications reduce chest leads or add new chest leads, and the chest leads adopt the same signal processing method: vi ═ Ci- (L + R + F)/3(i ═ 1, 2, 3.

Fig. 1 shows a conventional ecg signal acquisition circuit, the first stage is the signal source internal resistance of the cancellation electrode of the buffer amplifier (1, 2, 3, 4), the amplifier 11 synthesizes the wilson center potential, and the inverting amplifier 5 is used as the right leg driving circuit connected to the right leg RF electrode to cancel and reduce the common mode voltage amplitude of the whole system. The second stage is that differential amplifiers (12, 13, 14) eliminate common mode interference and amplify electrocardiosignals at the same time, so as to obtain standard electrocardiogram leads I, II and Vi (I is 1, 2, 3.

[ summary of the invention ]

The invention provides a novel multichannel electrocardiogram acquisition scheme, which comprises an electrocardiogram amplification circuit, an analog-to-digital conversion circuit and a related digital signal processing algorithm.

According to the novel multichannel electrocardiogram acquisition scheme, each channel can simultaneously complete buffer amplification (high input impedance) and differential amplification (high common mode rejection ratio) only by a single-stage operational amplifier, and chest leads do not need Wilson central potential. The novel acquisition scheme of the electrocardiograph can reduce nearly half of precision resistors and precision operational amplifiers, greatly simplifies an electrocardiograph preamplifier circuit, saves cost and reduces PCB space, simplifies the electrocardiograph amplifier circuit, reduces hardware fault rate, simultaneously reduces thermal noise introduced by the operational amplifiers and electromagnetic interference introduced by the external environment, can improve the signal-to-noise ratio of electrocardiograph waveforms, and has remarkable benefit.

In the above-mentioned novel multichannel electrocardiogram collecting scheme, an in-phase buffer-amplified output of a certain limb electrode (e.g. R electrode) is taken as a COM common terminal, other limb electrodes (L electrode, F electrode), N chest electrodes (Ci electrode, i is 1, 2, 3.., N) and the common terminal respectively form a multichannel dual-operational amplifier instrument amplifier, each channel is simultaneously buffer-amplified and differentially amplified by a single operational amplifier, and multichannel electrocardiogram waveforms X1, X2, XVi (i is 1, 2, 3.., N) are output. The electrocardiogram waveform is synchronously sampled into digital signals by a multi-channel analog-to-digital converter, and is corrected by a digital signal processing algorithm to calculate standard electrocardiogram leads I, II and Vi (I is 1, 2, 3.

According to the novel multichannel electrocardiogram acquisition scheme, the COM common end is subjected to reverse phase amplification and then fed back to a right leg electrode (RF electrode) as a right leg driving circuit to offset and reduce the common-mode voltage amplitude of the whole system.

The novel multichannel electrocardiogram acquisition scheme is proved by trial production and clinical trial: the design requirement is met, the amplifying circuit is simplified, the production cost can be obviously reduced, the noise is low, the interference is small, and the signal-to-noise ratio of the electrocardiogram waveform is improved.

[ description of the drawings ]

FIG. 1 is a schematic circuit diagram of a conventional ECG acquisition circuit;

FIG. 2 is a schematic circuit diagram of a first embodiment of the multi-channel ECG acquisition circuit provided by the present invention;

FIG. 3 is a schematic circuit diagram of a second embodiment of the multi-channel ECG acquisition circuit of the present invention;

fig. 4 is a schematic circuit diagram of a third embodiment of the multi-channel electrocardiogram acquisition circuit provided by the invention.

[ detailed description ] embodiments

The present invention will be described in further detail below with reference to specific embodiments and with reference to the accompanying drawings.

The first embodiment is as follows: the R electrode is used as a public end;

please refer to fig. 2: in the multi-channel electrocardiogram acquisition circuit of the present embodiment, the output of the non-inverting amplifier 1 of the R electrode is used as the common terminal COM, and the other electrodes: the L-limb electrode, the F-limb electrode and the Ci chest electrode (only 1 channel is drawn here) form typical double-operational

amplifier instrumentation amplifiers

2, 3 and 4 with the COM common end respectively to output X1, X2 and XVi signals, electrocardiosignals are amplified while common-mode interference is eliminated, and the amplification factor A is determined by resistance values R1 and R2 (A is 1+ R1/R2). The common terminal COM drives the RF electrode (right leg drive circuit) via the inverting amplifier 5.

Because the X1, X2 and XVi signals output by the double operational amplifier instrument amplifier are different from the standard leads of the electrocardiogram, after the analog-to-digital converter 6 completes synchronous sampling, the correction is completed by the following digital signal processing algorithm to obtain the standard electrocardiogram leads:

according to the following: x1 ═ a (R-L);

X2＝A*(R-F)；

XVi ═ a (R-Ci), where i ═ 1, 2, 3

To obtain: -X1;

lead II-X2;

vi lead-XVi + (X1+ X2)/3, where i is 1, 2, 3

Example two: the L electrode is used as a common terminal;

please refer to fig. 3: in the multi-channel electrocardiogram acquisition circuit of the present embodiment, the output of the non-inverting amplifier 1 of the L electrode is used as the common terminal COM, and the other electrodes: the R limb electrode, the F limb electrode, and the Ci chest electrode (only 1 channel is drawn here) form typical dual operational

amplifier instrumentation amplifiers

2, 3, and 4 with the COM common terminal to output X1, X2, and XVi signals, which are amplified while eliminating common mode interference, and the amplification factor a is determined by the resistance values R1 and R2 (a is 1+ R1/R2). The common terminal COM drives the RF electrode (right leg drive circuit) via the inverting amplifier 5.

Because the X1, X2 and XVi signals output by the double operational amplifier instrument amplifier are different from the standard leads of the electrocardiogram, after the analog-to-digital converter 6 completes synchronous sampling, the correction is completed by the following digital signal processing algorithm to obtain the standard electrocardiogram leads.

According to the following: x1 ═ a (L-R);

X2＝A*(L-F)；

XVi ═ a (L-Ci), where i ═ 1, 2, 3

To obtain: i-lead X1;

lead II-X1-X2;

vi lead-XVi + (X1+ X2)/3, where i is 1, 2, 3

Example three: the F electrode is used as a common terminal;

please refer to fig. 4: in the multi-channel electrocardiogram acquisition circuit of the present embodiment, the output of the non-inverting amplifier 1 of the F electrode is used as the common terminal COM, and the other electrodes: the R-limb electrode, the L-limb electrode, and the Ci chest electrode (only 1 channel is drawn here) form typical dual operational

amplifier instrumentation amplifiers

According to the following: x1 ═ a (F-R);

X2＝A*(F-L)；

XVi ═ a (F-Ci), where i ═ 1, 2, 3

To obtain: the I lead is X1-X2;

lead II ═ X1;

vi lead-XVi + (X1+ X2)/3, where i is 1, 2, 3

The foregoing applications are illustrative of the present invention in further detail in connection with specific preferred embodiments thereof, and the practice of the invention is not to be considered limited to these examples. Other simple deductions and substitutions can be made by those skilled in the art without departing from the technical idea of the invention, and all should be considered as the protection scope of the invention.

Claims

1. A novel multi-channel electrocardiogram acquisition method comprises an electrocardiogram amplification circuit, a multi-channel analog-to-digital converter and a related digital signal processing algorithm;

the multi-channel double-operational amplifier is characterized in that the output of in-phase buffering and amplification of a first limb electrode is used as a COM common end, a second limb electrode, a third limb electrode and N chest electrodes (Ci electrodes, i is 1, 2, 3.. and N) form a multi-channel double-operational amplifier with the COM common end respectively, each channel can simultaneously complete buffering and differential amplification of an electrocardiogram by using a single operational amplifier, and multi-channel electrocardiogram waveforms X1, X2 and XVi (i is 1, 2, 3.. and N) are output;

each channel of the electrocardiogram amplifying circuit simultaneously completes the buffering amplification and the differential amplification of the electrocardiogram only by using a single operational amplifier, and chest leads do not need Wilson central potential;

the output of the electrocardio amplifying circuit is converted into digital signals by the multi-channel analog-to-digital converter, and standard electrocardiogram leads I, II and Vi (I is 1, 2, 3.., N) are calculated by the digital signal processing algorithm, wherein the Vi lead-XVi + (X1+ X2)/3, I is 1, 2, 3..

2. The method as claimed in claim 1, wherein the multi-channel ECG waveform outputted from the ECG amplifying circuit is a non-standard ECG lead, which is synchronously sampled by the multi-channel A/D converter to be a digital signal, and then the standard ECG lead is calculated by the related digital signal processing algorithm.

3. The method for collecting the electrocardiogram according to claim 1, wherein the COM common terminal is connected to the right leg electrode (RF electrode) via an inverting amplifier to form a right leg driving circuit for reducing the common mode voltage amplitude of the whole system.