RU6989U1 - DEVICE FOR DETERMINING THE CRITICAL FREQUENCY OF FUSION FUSION FUSION IN CHILDREN - Google Patents

Abstract

A device for determining the critical flicker-fusion frequency, comprising a frequency divider, the first output of which is connected to one of the inputs of the I inhibit circuit, the second output of which is connected to the input of the pulse shaper ChSM, characterized in that, in order to improve the metrological characteristics of the device: linearity of frequency adjustment, smoothness and accuracy of its installation and providing a greater range of overlap introduced into it a quartz reference frequency generator, an adjustable variable frequency generator, the outputs of which are connected are connected to the inputs of the beat-frequency mixer-shaper, and the mixer output is connected to the beat-frequency divider input, the output of the reference frequency crystal oscillator is connected to the shaper of the measuring interval duration, the output of which goes to the other input of the AND inhibit circuit, and two two-color emitters are used at the output, and one through the color switch of the output stimulus is connected to the output of the ChSM pulse shaper, and the other stimulus of the same color glows constantly, the light sources are made in the form of toy car headlights tomobile.

Description

DEVICE FOR DETERMINING CRITICAL FREQUENCY OF MERGER

Flicker in children.

The utility model relates to medical equipment, namely, devices for conducting ophthalmological examinations in children of preschool and school age. A device for determining the critical fusion frequency of light flickers, which contains a power source, a voltage regulator, an overload protection unit, a pulse generator, a first frequency divider by 10, a second frequency divider with a variable division coefficient, a third frequency divider by 1000, a pulse power conditioner , light source and discrete frequency setting unit (1).

The disadvantage of this device is the duration of the study, the multi-stage determination of the critical fusion flicker frequency and the inability to change the color of the stimulus.

A device for studying the critical flicker fusion frequency is also known, which contains a first pulse generator, a second pulse generator / connected via a control panel to a light source and a processing unit connected to an indication unit, the processing unit consists of a frequency divider connected to an input with the second output of the control panel and with an output with a control trigger, which is connected to the And element, which is connected to the display unit, the test subject is connected to a light source and a control panel.

The disadvantage of this device is the inability to examine the lesion of the macular zone of the retina, optic nerve in children and change the color of the stimulus. The technical result achieved using this utility model is to increase the accuracy of the study of lesions of the macular zone of the retina and optic nerve. In addition, increases the accuracy of the study of cone and rod apparatus.

In addition, the child is more aware of what is required of him and the diagnosis takes place in the form of a game.

The purpose of the invention is to increase the accuracy and reliability of the results of a study of the critical frequency of flicker fusion in children of preschool and school age.

The device contains: a crystal oscillator of the reference frequency 1, an adjustable oscillator of variable frequency -2, a mixer and a shaper of the beat frequency -3, a beat frequency divider - 4, a pulse shaper ChSM - 5, a color stimulus color switch - 6, a shaper of the measurement interval duration - 7, prohibition circuit I - 8, pulse counter - 9, digital indicator of flicker fusion frequency ChSM-10, two-color emitters 11-12. The device operates as follows from a quartz oscillator - 1 and an adjustable oscillator 2, the signal is supplied, respectively, to the first and second inputs of the mixer-driver of the beat frequency 3, from the output of which pulses are fed to the frequency divider - 4, from the first output of the divider 4, the pulses are sent to one inputs of the ban circuit 8, the second input of this circuit receives a pulse of resolution of the count, from the output of the shaper measuring duration

- 2 i

interval 7, the input of this shaper, the signal comes from the quartz oscillator 1, from the second output of the divider 4, the pulses are fed to the pulse shaper FSM (flicker fusion frequency) where their constant duration and amplitude are set, then the signal goes to the color switch of the output stimulus 6, which the outputs are connected to two-color emitters 11 and 12, and operates as follows, pulses from the former 5 are sent to the emitter 11 to the red or green crystal of the emitter LED, which gives flashes of light th stimulus corresponding color, and a signal emitter 12, which allows the continuous flux of the corresponding color.

Figure 1 shows a block diagram of the device, Fig. 2 shows a General view of the device.

The determination of the critical frequency of flicker fusion (CFSM) is as follows: a child is introduced to a toy car (emitter) and, for example, it is suggested that the headlight be repaired before flickering stops first on the red stimulus, then on the green one, then light flickers appear on the emitter 11 with a frequency and a given color, moreover, on the digital indicator 10 the current value of the FSM is displayed, by changing the frequency of the generator 2, the moment of merging of the flickers is achieved, about which the child informs, the study is conducted several times h, to control the merger glimpses child uses continuous light stimulus, a second headlamp toy car 12.

Sources of information:

- 3 out flickers. Byul. N 44, 1990.

2. V.G. Brusnetsov, B.I. Beznosenko, Yu.I. Moroz, L.S. Nersesyan, A.S. N 1308317, cl. A 61 V 5/16

A device for studying the critical frequency of flicker fusion. Bulle. N 17, 1987.

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Compiled by LG to-in - Golubtsov.

Claims (1)

A device for determining the critical flicker-fusion frequency, comprising a frequency divider, the first output of which is connected to one of the inputs of the I inhibit circuit, the second output of which is connected to the input of the pulse shaper ChSM, characterized in that, in order to improve the metrological characteristics of the device: linearity of frequency adjustment, smoothness and accuracy of its installation and providing a greater range of overlap introduced into it a quartz reference frequency generator, an adjustable variable frequency generator, the outputs of which are connected are connected to the inputs of the beat-frequency mixer-shaper, and the mixer output is connected to the beat-frequency divider input, the output of the reference frequency crystal oscillator is connected to the shaper of the measuring interval duration, the output of which goes to the other input of the AND inhibit circuit, and two two-color emitters are used at the output, and one through the color switch of the output stimulus is connected to the output of the ChSM pulse shaper, and the other stimulus of the same color glows constantly, the light sources are made in the form of toy car headlights tomobile.