SU1008928A2 - Electroacoustic transducer - Google Patents

Abstract

ELECTRIC ACCELERATOR CONVERTER, auth. 900469, characterized in that, with the purpose of expanding its functional capabilities by measuring the constant component of the sound pressure, a switch is additionally introduced into it, the first input of the switch being connected to the output of the inverter, whose input is connected to the output of the second derivative block, the second input of the switch is with the output of the block of the second derivative, and the output of the switch is connected to the input of the adder. i (o

Description

This invention relates to acoustic measurements and can be used to measure the constant sound pressure component as an acoustic radiometer.

According to the main auth. 900469. Electroacoustic converter is known, which contains a condenser microphone, a differential transformer, equalizing capacitor, phase detector, high-frequency reference generator, first derivative signal determining unit, second derivative determining unit, inverter, adder and polarizing voltage source, with a condenser microphone, equalizing capacitor, and the differential transformer is connected according to the differential bridge circuit, one of the arms of which includes the first input of the phase detector, W The entrance of the phase detector is connected to the first output of the reference generator, the second output of which is connected to one of the inputs of the adder, to the other inputs of which the output of the phage detector is connected, the output of the first derivative block and the output of the inverter the inputs of the first and second derivatives are connected to the output of the phase detector, and the output block of the second derivative is connected to the input of the inverter 11.

A disadvantage of the known device is its inability to use it for accurate measurement of the constant component of the sound pressure.

The purpose of the invention is to expand the functionality of a known device by measuring the constant component of the sound pressure.

This goal is achieved by additionally introducing a switch into the electroacoustic converter, with the first input of the switch connected to the output of the inverter, whose input is connected to the output of the second derivative unit, the second input of the switch to the output of the second derivative unit, and the output of the switch connected to the input of the adder.

The drawing shows the proposed device.

The device contains a condenser microphone 1, an equalizer, a capacitor 2, a differential transformer 3, a phase detector 4, a high frequency reference oscillator 5, a block 6 of the first derivative, a block 7 of the second derivative, an inverter 8, an adder 9, a switch 10, a source 11 polarized de wives

Changes. The capacitance microphone capacitance 1 under the action of sound pressure leads to the imbalance of the differential bridge formed by the condenser microphone 1, the equalizer capacitance 2 and the differential transformer 3.

The error signal is sensed by the phase detector 4, the reference signal for which is the signal from the high-frequency generator 5. The audio signal taken from the phase detector 4 is fed to the first derivative block b, in which it is differentiated, and also to the second derivative 7 which doubles the differentiation of the signal. At the output of block 7, the second derivative is an inverter 8. Summato 9 performs the summation of signals from the outputs of the reference generator 5, phase detector 4, block 6 of the first derivative and switch 10, and switch 10, depending on the operating mode, can connect to adder 9 or the output of the second derivative block directly, or after the inverter. From the output of the adder 9, the signal through the source 11 of the polarizing voltage is supplied to the second shoulder of the differential bridge. The signals supplied to the differential bridge through the adder 9 from the output of the phase detector 4, blocks b and 7 of the first and second derivatives, respectively, automatically adjust the device according to position, speed and acceleration, respectively, i.e. affect the stiffness, damping and mass of the condenser microphone membrane. In the radiometer switch-on mode, the signal from the output of block 7 of the second derivative is fed through the switch to the adder 9 directly) all three signals of the feedback are fed to the condenser microphone in antiphase with the action of sound pressure. This leads to an increase in the stiffness of the membrane, an increase in its damping and weight. In the operation mode of the measuring microphone, the signals of the position and speed of the membrane are fed in antiphase, and the acceleration signal is in phase with sound pressure, which is carried out by applying a signal from the output of the second derivative unit to the adder through the inverter in the corresponding position of the switch 10. This corresponds to a decrease in the mass of the membrane at increasing its stiffness and damping.

An increase in the mass of the membrane during the operation of the device as a radiometer is necessary in order to exclude oscillations with a sound frequency, and to perceive only a constant component of the sound oscillations.

The use of the proposed device as a radiometer allows

J1008928

to achieve greater sensitivity in the circuit of the condenser mix with the known microphone radimeters and the improvement of the mechanical properties due to the use of the differential properties of its membrane.

Claims (1)

ELECTRO-ACOUSTIC CONVERTER by ed. "900469, about t - th X. +