JPH0580209B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for amplifying and detecting biological signals by attaching lead-out electrodes to the human body, and particularly relates to a device for amplifying and detecting biological signals derived from a total of 10 points in the limbs and the chest. This invention relates to a standard 12-lead electrocardiogram input device obtained by combining signals.

[Conventional technology]

Conventionally, the amplifier of this type of electrocardiogram input device outputs a 12-lead waveform synthesized by a resistor network by switching the leads every three channels and dividing the waveform into several parts. It became necessary, and the signals were not at the same time.
Furthermore, at least three isolation sections were required.

[Problems to be solved]

In the conventional electrocardiograph mentioned above, the 12-lead electrocardiogram is synthesized using a resistance network, and the output is switched four times, so it is impossible for the electrocardiogram to be from the same point in time, and the switching part, buffer, and resistance network cannot be output. There were errors in the workpiece, making the circuit complex and reducing reliability.

In addition, at least three isolation units are required, and the capacity of the isolation power supply for this is large.
There is also an increase in costs due to the increase in parts and an increase in failure rate due to the complexity of the circuit.

R-wave detection involves simple addition of 1-lead or 2-lead signals, and if the amplitude is small, it may become uncertain, or it may be detected at the falling point of the R wave, or it may be difficult to detect signals mixed with noise. There are problems such as false detection.

[Means for solving problems]

The present invention solves the above problems, and includes a main amplifier section having a differential amplifier that generates a signal of a target induction part from a plurality of signals including in-phase components, and a main amplifier section that has a differential amplifier that generates a signal of a target induction part from a plurality of signals including in-phase components; A maximum value selector that detects the maximum value, a bandpass filter that extracts the R wave from the signal detected by the maximum value selector, and a second-order differential of the R wave obtained by this bandpass filter and R-wave detection amplifier section that includes a half-wave rectifier circuit that extracts the rising edge of the differentiated R-wave, and a hysteresis comparator/generator that triggers this extraction result at a sufficiently high threshold and generates a detection signal with a constant pulse width. In other words, by combining signals of two or more arbitrary channels, an R wave signal with a larger amplitude is detected and a detection pulse synchronized with the R wave is generated.

〔Example〕

Next, an example thereof will be explained with reference to FIG.

FIG. 1 is a block diagram of a circuit of an embodiment of an electrocardiogram input device according to the present invention.

In the figure, this circuit roughly consists of main amplifier section 1, R
an isolation power supply 8 that supplies power to the detection amplifier section 2 and the isolation section of the amplifier;
It becomes more.

The main amplifier section 1 has 8 channels (hereinafter referred to as CH).
) consists of a differential amplifier 3, a multiplexer 4, an isolation amplifier 5, a sample hold 6, and an AD converter 7, and the necessary signals are only 8 channels, and the necessary 12 leads are = -R+
F, = -L + F, C'n = Cn - F (n = 1 to 6)
is captured at the same point in time, and when outputting later,
Calculated by software. Also, only one isolation amplifier 5 is added between the multiplexer 4 and the sample hold 6, and is insulated from the human body side.

Similarly, the insulated R detection amplifier section 2 receives two or more arbitrary signals into the maximum value selector 9, detects the larger R wave signal, and transmits the signal to the next bandpass filter 10 and half wave rectifier circuit. 11 and 2
The rising part of the differentiated R wave is extracted. Next, the hysteresis comparator 12A of the hysteresis comparator/generator 12 is triggered at a threshold sufficiently higher than the noise level, and the one-shot generator 12B generates a detection signal of a constant pulse value.

〔Effect of the invention〕

As explained above, in the present invention, an electrocardiographic signal is input using the isolated differential amplifier 3 of only 8 channels, and the signal is directly input as =FR for lead and =FL for lead. The induction is calculated from =-, then aV _R =-+
/2, aV _L =-+/2, aV _F = 1/2 (+), and as the chest Vn = C'n + 1/3 (+) (however, C'n = Cn - F (n = 1 to 6 )) by software, it is possible to output any combination of waveforms at the same point in time. In addition, the hardware is extremely simple as it can consist of exactly the same 8 channel amplifiers. Further, the single isolation amplifier 5 reduces the cost of the device and improves reliability at the same time. Furthermore, shield from reference signal F and N (right foot)
It is also possible to apply the effect to all channels by creating a drive signal. By increasing the maximum value selector 9 of the R wave detection signal input, signals of two or more arbitrary channels can be used for detection, and reliability can be increased. In addition, the values of band pass filter 10 are set to band width B = 6.8 and sharpness Q.
By selecting p = 2.1 and center frequency _p = 14.3 and combining it with the half-wave rectifier circuit 11, it is possible to always trigger at the rising edge of the R wave, making it possible to clearly separate it from the Q, S, and T waves.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a circuit of an embodiment of an electrocardiogram input device according to the present invention. 1... Main amplifier section, 2... R detection amplifier section, 3... Differential amplifier, 4... Multiplexer,
5...Isolation amplifier, 6...Sample hold, 7...AD conversion section, 8...Isolation power supply, 9...Maximum value selector, 10...
Bandpass filter, 11...Half wave rectifier circuit, 1
2...Hysteresis comparator/generator.

Claims (1)

[Claims] 1. A main amplifier section having a differential amplifier that generates a signal of a target induction site from a plurality of signals including in-phase components, and detecting the largest one among the plurality of signals from the main amplifier section. A maximum value selector, one bandpass filter that extracts an R wave from the signal detected by the maximum value selector, and a second-order differential of the R-wave obtained by this band-pass filter, and a second-order differentiated R-wave. It consists of a half-wave rectifier circuit that extracts the rising part of An electrocardiogram input device characterized in that it detects an R-wave signal with a larger amplitude by combining signals of two or more channels and generates a detection pulse synchronized with the R-wave. 2. The electrocardiogram input device according to claim 1, wherein the main amplifier section includes one isolation amplifier.