SU1250255A1 - Apparatus for investigating hearing - Google Patents

Description

The invention relates to medical technology, in particular to devices for objective audiometry.

The purpose of the invention is the differential diagnosis of central and peripheral hearing impairment.

FIG. 1 shows a structural electrical circuit of the device; in fig. 2 - diagrams, but removing the operation of the device; in fig. 3 - switch diagram; in fig. 4 is an integrator diagram.

The device contains (Fig. 1) an adjustment block 1, an adjustable oscillator 2 of audio frequency signals, connected via modulator 3 to audiometer 4, and control block 5, containing two flip-flops 6 and 7, pulse-connected oscillator 8, third flip-flop 9 and single-wave - torus 10, serially connected switch 11, analog integrator 12 and first comparator 13, serially connected adjustable voltage source 14 and second comparator 15, the second input of which is connected to the second input of the modulator 3 and to the first ode comparator 13, a second input coupled to a common schinoy. The control unit 5 also contains an element 16, the first input of which is connected to the output of the comparator 13, and the second input - with the inverse output of the trigger 9, the first inputs of the trigger 6 and 7 are connected to the first input of the trigger 9, the second inputs of the trigger 6, 7 and 9 connected to the input of the generator 8 and the Start 17 button. The third input of the trigger 9 is connected to the output of the comparator 15, the third input of the trigger 7 is connected to the output of the And 16 element, and the output to the reset input of the integrator 12, the one-shot output of the integrator 12 , the direct outputs of the flip-flops 9 and 6 are connected respectively with the first and second inputs of the switch 11, the third, fourth, fifth and sixth inputs of which are connected to the first, second, third and fourth outputs of the adjustment block 1, the input of which is connected to the output of source 14, and the generator 8 is designed as a pair generator pulses.

Adjustment unit 1 contains potentiometers 18 and 19 connected to source 14 of direct voltage, and inverters 20 and 21, and the output of potentiometer 18 is the sixth output of control unit 1 (the voltage of this output determines the rising speed of the first pulse in a pair of package) and connected to the input of the inverter 20, the output of which is the fifth output of the adjustment unit 1 (the voltage of this output determines the decay rate of the first pulse in a pair of audio parcels), the output of potentiometer 19 is the fourth output of the unit 1 (the voltage of this output determines the rate of rise of the front of the second pulse in a pair of audio parcels) and is connected to the input of the inverter 21, the output of which is the third output of the adjustment unit 1 (the voltage of this output determines the rate of decay of the second pulse in

a pair of audio packages).

Switch 11 (Fig. 3) contains a decoder 22 and analog switches 23-26, controlled by signals from the decoder 22, while the KTL chips 143 can be used as analog switches, and the MC155CH can be used as a decoder. In addition, as the analog switch 11 with digital control can be used, for example, MS 590KHI or MS 59IKHI.

The integrator 12 (FIG. 4) contains analog switches 27 and 28, resistors 29 and 30, a capacitor 31, and an amplifier 32.

The hearing device operates as follows.

A predetermined value of the frequency of the sound signals is established with the aid of the generator 2 of the audio frequency signals and a certain value of the intensity of the sound signals using an adjustable source 14 of constant voltage. In addition, each time for each test for distinguishing individual pulses in a pair of sound signals, a certain rate of rise and fall of the first pulse in a pair is set with a potentiometer 18, and with the help of potentiometer 19 a different value of the speed of rise and fall of a second pulse in a pair .

When you press the Start 17 button, triggers 6, 7, and 9 are zeroed with the signal X and the generator of 8 paired rectangular pulses is triggered. The first impulse of the generator 8 switches trigger 6 (FIG. 2, time t) and triggers 7, 9 are activated. As a result, the control signals Yi, Yg and Yj are set at the outputs of control unit 5 (Figs. I and 2). Before the signals Yt and Y, through the switch 11, the integrator 12 receives an analog signal Vcpi proportional to the rate of rise of the front of the first pulse in the pair; signal Yj resolves

integrator 12, the output voltage of which rises linearly with a speed determined by the magnitude of the signal. When the output voltage of the integrator 12 reaches the threshold of the comparator 15 (the threshold was set using an adjustable source 14 of constant voltage), an output Xg appears in its output (Fig. 2, time tg), which returns the trigger 9 to its original state and starts the one-shot 10,

the duration of the output pulse Y / of which determines the duration of the vertex of the sound signal. Impulse 1, enters the input of the ban of the integrator 12, prohibits

integration over the time of the signal Y / ,. Simultaneously with the launch of the one-vibrator 10 (time t), the signal Yg disappears, with the result that the signal Vc, j, which determines the decay rate of the first pulse in the pair, goes to the input of the integrator 12 from the adjustment unit 1. At the end of the pulse. At the single-oscillator 10 (instant 1h), the integration process is resumed, but since the signal V has the opposite polarity with respect to the signal Uf1 acting on the time interval t. ,, tg, the voltage drops linearly at the output of the integrator 12. At the moment of time it, the comparator 13 is triggered and the signal X}, coming from the comparator 13 to the element AND 16, zeroes the trigger 7, which, in turn, zeroed the integrator 12 with the signal Yj.

Thus, at the output of the integrator 12, an LI / trapezoidal signal is generated, which is fed to the second input of the modulator 3, which modulates the signal of the generator 2 audio frequency signals fed to its first input. The amplitude-modulated sound signal (Fig. 2, voltage Ua) sounds in the telephone of the audiometer 4. This is how the first of the pair of device sound signals is formed.

At the moment is the action of the second pulse (Fig. 2) of the generator 8 of paired pulses, trigger 6 overturns into the opposite state, triggers 7, 9 are activated and the process of forming the second of a pair of trapezoidal pulses begins. However, due to the fact that at the considered period of time, the first control input of the analog switch 11 has a low level of the control signal YI, from the adjustment unit 1, via the switch 11, the input of the integrator 12 receives the signal Uf, which determines the rising edge rate the second trapezoidal pulse in the pair, and during the formation of the second trapezoidal pulse slice (time interval tr, tg) the integrator 12 receives a signal Vc, which determines the speed of the second slice pulse in the pair. Thus, the second of the pair of sound signal is formed (voltage Uj, Fig. 2).

To create another pair of beeps, you must click the button “Start 17 of the device.

The proposed hearing test allows the central hearing loss to be differentiated from the peripheral hearing by distinguishing the patient with different rates of rise and fall of each sound pulse in a pair of sound signals. If a patient with impaired hearing, using a audiometer telephone, a pair of sound pulses with different speeds of rise and fall of individual impulses in a pair, distinguishes different speeds of rise and fall of individual impulses, peripheral hearing loss occurs; if the patient does not distinguish between the difference in the rate of increase and decrease in impulses, a central hearing loss occurs.

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Claims (1)

DEVICE FOR STUDYING HEARING, comprising a control unit, an adjustable audio signal generator connected through a modulator to an audiometer, and a control unit containing two triggers connected in series with a pulse generator, a third trigger and a single-shot, characterized in that, for the purpose of differential diagnosis of a central and peripheral hearing impairment, the Start button, serial-connected switch, integrator and first comparator, series-connected adjustable source a DC voltage source and a second comparator, the second input of which is connected to the second input of the modulator and to the first input of the first comparator, the second input of which is connected to a common bus, an additional element And, the first input of which is connected to the output of the first comparator, is additionally introduced into the control unit, and the second input is with the inverse output of the third trigger, the first inputs of the first and second triggers are connected to the first input of the third trigger, the second inputs of all three triggers are connected to the input of the pulse generator and the Start button, the third the third trigger stroke is connected to the output of the second comparator, the third input of the second trigger is connected to the output of the And element, and the output is connected to the integrator's “Reset” input, the single-vibrator output is connected to the integrator's “Ban” input, the direct outputs of the third and first triggers are connected respectively to the first and the second inputs of the switch, the third, fourth, fifth and sixth inputs of which are connected to the first, second, third and fourth outputs of the control unit, respectively, the input of which is connected to the output of an adjustable constant current source zheniya, a pulse generator is designed as a pair of rectangular pulse generator. 1250255 D1