SU424560A1 - LARYNGOSTROBOSKOP - Google Patents

Description

one

This invention relates to a medical annuity for examining the vocal cords, namely laryngostroboscopes.

Known laryngostrobods are known, which include a microphone, an audio amplifier, a selective amplifier, an impulse formation circuit, a phase delay circuit, a setter for the law of change of the delay phase, a frequency meter, a power amplifier, and a stroboscopic lamp with an ignition system. The principle of operation of such devices is based on the stroboscopic effect: the frequency of flashes of a pulsed stroboscopic lamp illuminating the vocal cords is equal to or a multiple of the frequency of the dominant (fundamental) oscillations of the vocal cords. However, a change in the brightness of the vocal cords, due to a change in the brightness of the strobes of the stroboscopic lamp depending on the frequency of the signal (the frequency of the dominant oscillations of the vocal cords of the patient) applied to the input of the electronic laryngostrobod, complicates the study of the vocal cords, increases the fatigue of the vision of medical personnel and the process of photographing voice links.

The purpose of the invention is to obtain equal pulsed illumination of the vocal cords at different frequencies of their oscillations. To do this, in the laryngostroboscope a phase-delay phase connected between the output of the phase delay circuit and the power amplifier input is a frequency divider by two, made in the form of a trigger with a counting start, and a frequency limiter made in the form of a single-state device with one stable state, and the second power amplifier connected between the output of the phase delay circuit and the input of the ignition system of the stroboscopic lamp.

FIG. 1 shows a block diagram of the proposed laryngostroboscope; in fig. 2 is a schematic diagram of a frequency divider by two n frequency limiters.

A laryngostroboscope contains microphone 1 (nanometer-laryngophone), which converts mechanical vibrations into an electrical signal. The received signal is fed to the input of the amplifier 2 low frequency. Amplified electrical signals are fed to the input of the selective amplifier 3. which contains a double T-shaped bridge. Amplifier 3, the selection of the dominant frequencies of the vocal cords occurs. Selected dominant, and the frequencies arrive at the input of the former 4 pulses. The generated pulses are fed to the input of a phase delay circuit 5, which is designed to illuminate the vocal cords at times, the primary phase

states of x Circuit 6 is a device

3

which specifies the law of phase change (sawtooth, linear, etc.).

From the output of the phase delay circuit 5, the signal is split apart and nostunet directly to the amplifier 7 of the night network. Once Ie oo, this signal is sent to the input of frequency limiter 8, which works in conjunction with frequency divider 9 for two frequencies. Then the signal is sent to the power amplifier 10 connected to the ignition system 11 of the stroboscopic lamp, the input of which is also connected to the output of the power amplifier 7. A frequency meter 12 is also provided in the laryngostroboscope to measure the dominant vibration frequency of the vocal chords.

Frequency divider circuit 9 is assembled on two transistors 13 and 14 (Iem. Fig. 2) and is a trigger with a counting snusk, and frequency limiter 8 is a one-way switch performed on transistors 15 and 16 according to the circuit with automatic shift1, ennem. The circuit has one state of stable equilibrium (when transistor 15 is open, and transistor 16 is closed) and one state of unstable equilibrium (when transistor 15 is closed, and transistor 16 is open). The transfer of the circuit from the first state to the second is carried out by pulses of negative polarity applied to its input. The time during which the scheme is in a state of unstable equilibrium is determined by the parameters of the scheme, i.e. elements 17 and 18. The scheme returns automatically to a state of stable equilibrium.

The principle of frequency limitation is based on the fact that while the circuit is in an unstable equilibrium state, transistor 15 is saturated and the circuit does not respond to negative polarity pulses. Therefore, the maximum frequency of the output of the one-shot can be limited by the value determined by the parameters of the elements 17 and 18.

A stroboscopic effect appears only when the frequency of the flashes by the pulse of a lighting lamp is equal to the frequency of movement of the vocal cords. The stroboscopic effect is also preserved if the frequency of the fnon flashes is a multiple of the object's frequency / o5. In this case, the object is illuminated after every second, third, etc. turn. The mathematical expression of this effect is

/ sen 1

/ obP

where / g 1, 2, 3.

To satisfy this condition, the frequency of flashes of light should be less (by a factor of several times), or, at least, equal to the frequency of the object's oscillations.

This is done by a frequency limiter operating in conjunction with a frequency divider.

by two. In this case, the formula for the ratio of the charge of flashes to the frequency of movement of an object has the following form:

Ls1 ... J

/ about 2

The frequency limiter together with the frequency divider for two works as follows.

The limiter circuit is tuned to a predetermined forp frequency. The frequency divider divides any frequency coming to its input by two. If a signal arrives at the input, the frequency / in which is less than forp, i.e., then

the circuit skips this bit without changing, and the frequency of flashing / strobe lamia is

/ ogre

fa

since in this case only the frequency divider by two works. In the case of the arrival of a signal with a frequency, an automatic division of the beach into the next even number of times occurs, i.

f - / ogre / vsp - --- 2n

so that the desired frequency ratio is always maintained.

Thus, the flash rate of the strobe lamp will determine the expression. M:

r / on s / apr - „- / ogre

The smaller the flash frequency of the stroboscopic lamp, the less the integral light of the object changes.

Subject invention

Laryngostroboscope containing microphone, audio frequency amplifier, selective

an amplifier, a pulse shaping circuit, a phase delay circuit, a setpoint for the law of changing the phase of the delay, a frequency meter, a power amplifier, and a stroboscopic lamp with an ijig system characterized in

that, for the purpose of equal immersive illumination of the vocal cords at different frequencies of their oscillations, it establishes in series between the output of the phase delay circuit and the input of the power amplifier

frequency divider by two, made, for example, in the form of a trigger with a counting start, and a frequency limiter, made, for example, in the form of a single vibrator with one steady state, and a second power amplifier connected between the output of the phase delay circuit and the input of the strobe lamp ignition system .