SU1364295A1 - Apparatus for contactless recording of bogie citric signals - Google Patents

Abstract

A device for contactless recording of biosignals contains an electrode 1 connected in series with a dielectric layer 2, a resistor 3, a controlled oscillator 4, a first frequency multiplier 5, a reference oscillator 6, a second frequency multiplier 7, a DC amplifier 8, recorder, a phase detector 9, the inputs of which are connected to the outputs of the first and second multipliers 5 and 7 of the frequency, and the output to the DCF 8, low-frequency filter 10, synchronized generator 11, capacitors 12 and 16, inductance coil 13, varicaps 14,15,17. The purpose of the invention is to improve the measurement accuracy by eliminating the relative instability of the generators. 13 hp f-ly, 1 ill. -f $

Description

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The invention relates to medical technology, namely, devices for recording parameters of bioelectric signals without conducting contact of the sensing electrode with the patient's body, for example, for studying the bioelectric signals of the heart.

The purpose of the invention is to improve the measurement accuracy by eliminating the relative instability of the generators.

The drawing shows the functional diagram of the device.

A device for contactless recording of bioelectric signals contains an electrode 1 connected in series with a dielectric layer 2, a resistor

3, a controlled oscillator 4, a first frequency multiplier 5, as well as a reference oscillator 6 connected to the second frequency multiplier 7, and a DC amplifier 8 connected to a recorder (not labeled).

The device also contains a phase detector 9, the first and second inputs of which are connected, respectively, to the outputs of the first frequency multiplier 5 and second frequency multiplier 7, and the output to the DC amplifier 8. The input of the low frequency filter 10 is connected to the output of the DC amplifier 8, and the output to the second input of the generator 4, the third input of which is connected to the output of the reference generator 6. The generator 4 is configured to synchronize it.

The generator 4 contains a synchronized generator 11, the first capacitance 12, connected between the third input of the generator 4 and the input of the synchronized generator 11, the oscillating circuit of which is connected between its input and the total thickness and contains inductance 13 connected in parallel, the first variable 14 and the second variable 15, common point which is the first input of the generator

4, the second tank 16 and the third varicap 17 connected in series, the common point of which is the second input of the generator 4.

The device works as follows.

When the sensing element 1 is affected, for example, a pulse of a bioelectric signal, the phase of the high-frequency oscillations proportional to its amplitude at the output of generator 4 by the value d, and at the output of frequency multiplier 5 by NAtf, where N is the frequency multiplication factor, relation to the phase of oscillations in the reference channel at the output of frequency multiplier 7.

Therefore, at the output of the phase detector 9, there is a voltage variation by an amount proportional to the magnitude of the phase change.

When this generator 4 operates as follows. The frequency of the oscillator 11 by means of 5 initial (after manufacturing) tuning of the inductance 13 of the oscillating circuit is set equal to the frequency of the reference oscillator 6, and then due to the operation of the phase auto-d frequency control (PLL) through the filter 10, this equality is maintained constant.

In addition, the oscillations of the generator 11 are synchronized by the oscillations of the reference generator 6 due to the presence of a coupling element between them - the capacitance 12.

The time constant of the low-frequency filter 10 is set 3-5 times longer than the maximum period of the signal under study, i.e. on the order of 30-50 seconds, which, on the one hand, excludes the triggering of the filter

20 at the frequencies of the studied bioelectric signals (0.1–100 Hz), and on the other hand, it constantly maintains the frequency of the synchronizing generator 11 in the capture band by oscillations of the reference generator 6.

25 In connection with this, the oscillations of the synchronized generator 11 vary only in phase, and their average frequency is equal to the frequency of the reference oscillator.

Thus, due to the introduction of 30 synchronization of the generator 4 and its coverage by the PLL system, it became possible to eliminate the error due to the mutual instability of the frequencies of the generator 4 and the reference generator 6.

35

Claims (2)

1. Device for contactless recording of bioelectric signals, containing electrodes connected in series 4Q with a dielectric interlayer, a resistor, a controlled oscillator and the first frequency multiplier, a reference oscillator connected to the second frequency multiplier and a DC amplifier connected to the recorder, characterized in that, in order to improve the measurement accuracy by eliminating the relative instability of the generators, It introduced a phase detector, the first and second inputs of which are connected respectively to the outputs of the first and second frequency multipliers, and the output to the DC amplifier, low-pass filter, in d is connected to the output of the DC amplifier, and the output - to the second input of the controlled oscillator, whose third input is connected to 55 by the output of the reference oscillator, the controlled oscillator is made synchronized. 2. The device according to claim 1, characterized in that the controlled generator comprises a sync35 Invention Formula five 1. Device for contactless recording of bioelectric signals, containing electrodes connected in series Q with dielectric interlayer, resistor, controlled oscillator and first frequency multiplier, reference oscillator connected to second frequency multiplier and DC amplifier connected to recorder, characterized in that, in order to improve measurement accuracy by eliminating the relative instability of generators, It introduced a phase detector, the first and second inputs of which are connected respectively to the outputs of the first and second frequency multipliers, and the output to the DC amplifier, low-frequency filter, input which is connected to the output of the DC amplifier, and the output - to the second input of the controlled oscillator, whose third input is connected to 5, the output of the reference oscillator, the controlled oscillator is made synchronized. 2. The device according to claim 1, characterized in that the controlled generator contains sync2 13642954 generator, the first capacitor, the inductance, the opposite connected between the third control input, the first and the second varicaps, the common point of the generator and the synchronizer input is the first input of the generator, the oscillator, the oscillating circuit connected in series between the entrance and the ob-5 bone and the third varicap, the common point of which is bus and contains connected paral-ry is the second input of the generator.