SU733640A1 - Apparatus for registrating biological signal - Google Patents

Description

one

The invention relates to medical technology, namely to electrophysiology.

A device for recording a biological signal is known, which contains electrodes, a bandpass amplifier, a threshold circuit, a recording device connected in series, and a waiting one-shot

However, in the presence of interference, the release of a biological signal by this device is not sufficiently reliable.

The aim of the invention is to improve the reliability of the selection of a biological signal in the presence of interference.

The goal is achieved by introducing a frequency converter into voltage, a nonlinear converter, a start circuit and a key circuit, the inputs of frequency converters to voltage and start circuits are connected to the output of the threshold circuit, the output converter of the voltage into voltage. through nonlinear converter

And the output of the start circuit is connected to the inputs of a standby one-shot, the output of which is connected via a key circuit to the control input of the amplifier.

The waiting odnnobrator is made controlled.

Non-linear pre1: the die is made up of a chain of diodes with different bias voltages.

FIG. 1 shows the structural scheme 4i

10 mA device for recording a biological signal; in fig. 2 - timing charts of the device.

The device contains electrodes 1, a bandpass amplifier 2, a threshold circuit 3 connected in series, and a registering device 4. In addition, the device contains a frequency-to-voltage converter 5, a non-linear converter 6 waiting for a vibrator

20 torus 7, start circuit 8 and key circuit 9. The inputs of the frequency converter 5 to voltage and the start chains 8 are connected to the input of the threshold circuit 3, and the output of the converter 5 through the nonlinear converter 6 and the output of the start chain 8 are connected to input x and 10 11 of the standby one-shot 7. The output of the stand-by one-shot 7, which is made controlled by the key circuit 9, is connected to the control input of the amplifier 2. The non-linear converter 6 is made in the form of a chain of diodes with different bias voltages.

The device works as follows.

A biological signal, for example, an electrocardiogram having a periodic structure, and one of the informative sections of which is necessary to distinguish, for example a tooth, is taken with the help of electrocardiographic transducer 1 and fed to amplifier 2. In FIG. 2a shows the initial electroscopic and diographic signal at the amplifier output and the threshold level of the Supports.

The threshold circuit 3, to the input of which an amplified biological signal is fed, generates output rectangular pulses, the fronts of which correspond to the moments of crossing the threshold level Unop-P at its input; the pulse duration is equal to the time between two adjacent intersections. nor mi threshold level. FIG. 26 depicts the Unc input pulses on the threshold circuit, obtained as a result of the intersection of the electrocardiogram elements, in particular, the R and T-wave threshold levels. The useful signals in this case are pulses corresponding to the R-teeth. Pulses that correspond to T-teeth are spurious pulses, which, for example, when changing the frequency of cardiac contractions, reduce the accuracy of the measurement.

The output pulses of the threshold circuit 3 are fed to the converter 5, on. the input of which is given a constant, slowly varying voltage Uf.pW, the magnitude of which is proportional to the frequency F of the useful signal (Fig. 2c). This voltage is converted by a non-linear converter 6 into a stationary (slowly varying) voltage proportional to the follow-up period of the output pulses of the threshold circuit (Fig. 2d).

The output pulses of the threshold circuit 3 are generated by the trigger circuit 8 and fed to the one-shot trigger input 10

launch it. At the input of the controlled stand-alone one-shot 7, pulses are generated, the duration of which varies depending on the voltage on the control input 11 of the one-shot 7, which is the output voltage of the non-linear converter 5

The type of signals at the output of the controlled standby one-shot is shown in FIG. 2d. These pulses control the operation of the key circuit 9 so that the key circuit provides for locking without saturating the amplifier during the formation of a one-shot pulse, and after this pulse is terminated, the amplifier quickly opens and ensures that the next signal passes.

Claims (3)

1. A device for recording a biological signal, containing electrodes, a bandpass amplifier, a threshold circuit, a recording device connected in series, and a waiting one-shot, characterized in that, nonlinear converter, start-up circuit and key circuit, with the inputs of the frequency to voltage converter and the starting circuits are connected to the output of the threshold circuit, the output of the frequency converter to voltage is through a non-linear converter, and the output of the trigger circuit is connected to the inputs of a standby one-oscillator, the output of which is connected to the control input of the amplifier through a key circuit. 2. Device pop. 1, characterized in that the waiting one-shot is controlled. 3. The device according to claim 1, characterized in that the non-linear converter is made in the form of a chain 57336406. diodes with different voltages, cm-1. Utkin V.A. and others. Interferences scheni Sources of information taken into account during the examination autonomous cardiolider, Theory and practice of physical culture № 10, 1971.