SU953549A2 - Sound absorption factor measuring device - Google Patents

Description

one

The invention relates to instrumentation and can be used in acoustic measurements.

According to the main auth. USSR No. 697912 discloses a device for measuring sound absorption coefficient, comprising a sweeping frequency generator, an output connected to a sound pressure receiver and a feedback amplifier, and a recorder, whose input is connected to the output of the feedback amplifier and radiator l.

The drawback of the device is that it does not automatically measure the sound absorption coefficient.

The purpose of the invention is to provide automation of measurements.

This goal is achieved by the fact that a device for measuring sound absorption coefficient, containing a oscillating frequency generator, an output connected to an acoustic pressure receiver and a feedback amplifier, a recorder whose input is connected to the output of the feedback amplifier and radiator, is equipped with a second

, a sound pressure receiver, an input-switch connected to it, the second input of which is connected to the first sound pressure receiver, an output - to the input of the reverse amplifier

(About the link and connected in series indicator of frequency characteristics, peak detector and converter sign-code, the first input of the indicator of frequency characteristics is connected to the output of the feedback amplifier and emitter, the second input to the second output of the oscillator

. frequency, and the second output - to the input of the recorder.

20. The drawing shows the block diagram of the device.

Claims (1)

The device for measuring the sound absorption coefficient comprises an electrically connected acoustic emitter 1, a first sound pressure receiver 2, a second sound pressure receiver 3, a switch, and a first and second input connected respectively to sound pressure receivers 3 and 2, output with feedback amplifier 5 and the first output of the oscillating frequency generator 6, connected in series by the frequency response indicator 7, the peak detector 8 and the analog-code converter 9 the first input of the indicator 7 of the high-voltage characteristics a connected to the output of the amplifier 5 feedback and the emitter 1, the second input - to the second output of the swept frequency oscillator 6 and the second output -; .to recorder input 10. The device works in a dull manner ... With the DO position. the contacts of the switch L and the supply of signals from the oscillator 6 of the oscillating frequency to the indicator; The characteristic of an electroacoustic system consisting of radiator 1, sound pressure receiver 2 and feedback amplifier 5. Visually, this characteristic is recorded on the recorder 10. This position of the contacts of the switch k corresponds to peaks of the amplitude-frequency characteristic described by the relationship: it,. . The transfer function of the emitter 1 and the sound pressure receivers 2 and 3; the distance between the emitter 1 and the sound pressure receiver 2; 06 - absorption coefficient. When the contacts aS of the switch i are located, the amplitude-frequency characteristic of the electroacoustic system consisting of the emitter 1 is taken; receiver 3, sound pressure amplifier 5 feedback. This position of the contacts of the switch k corresponds to the peaks of the amplitude-frequency characteristic, described by the dependency of the bridge, where xj is the distance between the emitter 1 and the receiver 3 of the sound pressure. Here, it is assumed that the transmission coefficients of the sound pressure receivers 2 and 3 are identical. From expressions (1) and (2), the following relationship is obtained: (licM) k. The magnitude of the peaks is measured by a peak detector 8 connected to the output of the indicator 7 of frequency characteristics. The signal from the output of the peak detector 8 is fed to the input of the converter 9 analog-code, the purpose of which is to convert analog information about the amplitude-frequency characteristic into information convenient for input into an electronic computer. The computer introduces a program corresponding to dependence 3, so that data on the sound absorption coefficient is directly received from the computer output. The use of the proposed device will improve the measurement performance 5-O times. Claims of Invention A device for measuring sound absorption coefficient according to ed. If 697912, characterized in that, in order to ensure the automation of the measurements, it is provided with a second sound pressure receiver connected with an input by a switch, the second input of which is connected with the first sound pressure receiver, the output with an input of a feedback amplifier, and connected in series by a frequency response indicator, a peak detector and an analog-to-frequency converter, the first frequency response indicator is connected to the output of the feedback amplifier and the emitter, the second input to the second output of the generator a swept frequency, and the second output - to the input of the recorder. Sources of information taken into account in the examination 1. USSR certificate of authorship If 697912, cl. G 01 N 29/00, 1978 (prototype).