RU2107464C1 - Method for transmitting electrocardiograms - Google Patents

Abstract

FIELD: medical engineering. SUBSTANCE: device has electrodes, repeaters, leads switch connected in series. The leads switch has frequency divider, leads switch pushbutton connected to its inputs. Differential amplifier, operation amplifier, voltage-controlled oscillator, power amplifier connected to dynamic loudspeaker are connected in series to its output. Leads switch control unit, transmission mode switch mounted between leads switch pushbutton and leads switch are additionally introduced into leads switch control unit design. Leads switch control unit is mounted between frequency divider and transmission mode switch. The frequency divider is connected to voltage-controlled oscillator output. Leads switch control unit has binary counter monovibrator and key connected in series. EFFECT: enhanced accuracy of operation; improved performance characteristics. 2 cl, 1 dwg

Description

 The invention relates to medical equipment, namely to devices for remote monitoring of the state of the cardiovascular system of patients.

 A number of devices are known for transmitting an electrocardiogram by telephone and containing a transmitter, the main parts of which are an electrode block, a switch, an amplifier and a modulator, as well as additional devices for transmitting a lead number before an ECG signal (ed. St. USSR N 1286158, MKI A 61 B 5/04), to reduce the level of interference when switching ECG leads (ed. St. USSR N 1287842, class A 61 B 5/04), to prohibit the transmission of an electrocardiogram when the electrodes on the skin of a person are poorly contacted (ed. St. USSR N 1827164, MKI: A 61 B 5/04). However, all these devices do not provide an automatic mode of transfer of leads and their complexity due to the introduction of additional devices into the circuit cannot but introduce distortions during ECG transmission.

 Closest to the proposed device is the EKP-9 electric cardiac transmitter developed by the Almaz association of the city of Saratov (Technical description and instruction manual. OMM3.530.010 TO, 1992). It consists of a series-connected electrode block, a repeater block and a lead switch, the second input of which is connected to the second output of the lead switch button, the first output of which is connected to the zero potential bus, the third input is to the output of the frequency divider, the input of which in turn is connected to the output generator frequency calibration signal amplitude of 1 mV, and the output through a series-connected differential amplifier, operational amplifier, voltage-controlled generator, power amplifier and is connected to the input of the speaker. The disadvantage of the prototype is that, firstly, the switching of leads during ECG transmission is done only manually, by pressing the switch button of the leads and, secondly, a special generator is used to generate a calibration signal with an amplitude of 1 mV of a certain frequency, which introduces additional distortions into the transmitted cardiac signal. Thus, this device does not provide high accuracy and noise immunity of the transmission of the electrocardiogram.

 The purpose of the invention is to improve the accuracy of the device while improving the convenience of its operation.

 The essence of the invention lies in the fact that in the device for transmitting an electrocardiogram, containing a series of electrodes, a repeater unit and a lead switch, the second input of which is connected to the output of the frequency divider, and the output through a series-connected differential amplifier, operational amplifier, voltage-controlled generator, amplifier power is connected to the speaker input, and a potential button, the control unit for the lead switch and the lane mode switch are additionally introduced dacha, the first input of which is connected to the second output of the lead switch button, and the output to the third input of the lead switch, with the input of the lead switch control unit connected to the output of the frequency divider, and the output to the second input of the transfer mode switch, and the input of the frequency divider to the output of a voltage controlled generator. In addition, the lead switch control unit is made on a binary counter connected in series, the counting input of which is the input of the unit, a single vibrator, the output of which is connected to the binary counter reset input, and a key, the information input of which is connected to the zero potential bus, the control input is with the output of a single vibrator , and the output is the output of the block.

 The drawing shows the proposed device.

 Designations: 1 - electrodes; 2 - repeaters; 3 - lead switch (ON); 4 - lead switch button; 5 - differential amplifier; 6 - operational amplifier (OS); 7 - voltage-controlled generator (VCO); 8 - power amplifier (PA); 9 - speaker; 10 - frequency divider; 11 - control unit switch leads (BUPO); 12 - transmission mode switch; 13 - binary counter; 14 - one-shot; 15 is the key.

 Unlike the prototype, the lead switch control unit (BUPO) 11 in the proposed device allows to expand its functionality - the ability to work in manual and automatic modes. The proposed connection of the VCO 7 with a frequency divider allows you to dispense with the formation of a calibration signal with an amplitude of 1 mV and automatically switch leads without an additional generator, as in the prototype, which reduces the level of distortion of the transmitted electrocardiogram. The apparent simplicity of the proposed solution, which consists in connecting the VCO 7 with the input of the frequency divider, is not obvious, because during the transmission of the calibration signal with an amplitude of 1 mV, the frequency of the generator 7 remains almost constant (the frequency deviation does not exceed ± 1.5%), which leads to a change in the frequency of the calibration signal and the switching time of the leads.

 The input signal from the frequency divider 10 is fed to the input of the binary counter 13, which generates a trigger pulse of a single-shot 14, forming a short pulse that controls the key 15 and translates the binary counter 13 to its initial position. In the presence of a control signal, the key 15 closes its output with a common point in the circuit. Depending on the position of the transfer mode switch 12, a control signal is supplied to the input of lead switch 3 either from the button for switching leads 4 or from BUPO 11.

 Example. All circuit elements in this embodiment of the proposed device are presented in accordance with the foregoing. A special embodiment of block 11 is due to its purpose in this device. As a single vibrator 14, a standby multivibrator containing an OR element is used. Its normal output level is low, the output pulled pulse is positive, and τ = 2 / 3RC, where R and C are the values of the elements in the waiting multivibrator. (see V. L. Shilo, Popular digital microcircuits. - M .: Radio and communications, 1988, p. 219). The pulse duration can be selected over a wide range. For example, from 10 to 10 ms. In the drawing, in the binary counter 13, the following notation is used: C is the counting input, R is the reset input, Q is the output, accepted conventions in the literature. Managed key 15 in this embodiment is an integrated circuit series K561KI3. each key has an output and a signal input, as well as an input for permitting the signal passage, the resistance of the switched-on channel is 80 Ohms, which is equivalent to the contact resistance of the pressed button. (See the reference book of V.L.Shilo Popular digital microcircuits, p. 227). Thus, it is possible to control the switching of leads by pressing button 4, or automatically under the control of an electronic circuit, depending on the position of the transfer mode switch 12.

Claims (2)

 1. An electrocardiogram transmission device comprising a series of electrodes, a repeater unit and a lead switch, the second input of which is connected to the output of the frequency divider, and the output is connected through a differential amplifier, an operational amplifier, a voltage-controlled generator, and a power amplifier connected to the speaker input, and a lead switch button, the first terminal of which is connected to the zero potential bus, characterized in that a switch control unit is inserted into it m leads and a transfer mode switch, the first input of which is connected to the second output of the lead switch button, and the output to the third input of the lead switch, while the input of the lead switch control unit is connected to the output of the frequency divider, and the output to the second input of the transfer mode switch, moreover, the input of the frequency divider is connected to the output of the voltage-controlled generator.  2. The device according to claim 1, characterized in that the lead switch control unit is made on a binary counter connected in series, the counting input of which is the input of a block, a one-shot, the output of which is connected to the binary counter reset input, and a key, the information input of which is connected to the bus zero potential, the control input is with the output of a single vibrator, and the output is the output of the unit.