SU493043A1 - Method for measuring the symmetry of the directivity pattern of microphones - Google Patents

Description

(54) METHOD OF MEASURING SYMMETRICITY

I Bor through amplifier and detector at TOV | the same transmission coefficient as in the previous case and consider the meter readings showing the ratio of the signal from the 2nd direction to the directional signal directly in percent or relative values,

normalized to I.

Summary of the Invention

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The proposed method consists in placing the microphone 1 in front of the radiator 2 so that the microphone is turned towards the radiator with the front surface of the diaphragm. A calibrated acoustic pressure is supplied from the radiator to the microphone. The electrical signal, removed from microphone 1, is fed to amplifier 3, from the amplifier output, the signal is sent to controller 4, and then through the detector 5 to the measuring device

6 ...

Regulator 4 manually or automatically. the signal level is normalized to a strictly defined level. In this case, the meter: the i device gives a reading of 100% or i, i.e. the signal level is applied equal to 100% or I

Microphone 1 is deployed to radiate any second direction, such as the back surface of the diaphragm, and feeds a signal from microphone 1 through amplifier 3, controller 4, detector 5 to meter 6 at the same position of controller 4 as when measuring the front signal .

Suppose the signal taken in the second case from microphone 1 is smaller than the signal

In addition in the first case, in some number, times less. Since the signal level in the first case is normalized to 1OO% (1), the instrument in the second case will show

and

I shall call that number of percents which corresponds to the signal. In the second case with respect to the first. Similarly, the instrument will show the percentage of the signal in the second case to the signal in the first case, if the signal in the second case is greater than the signal in the first case, only this ratio will be (more than 100% (greater than one). The scale of the measuring device is calibrated in percent or relative units The 100% mark (1) is located approximately in the middle of the scale.

The invention

A method of measuring the symmetry of the directivity characteristics of microphones, which consists of amplification, detection, measurement, and comparison: of signals taken from a microphone when an acoustic signal is fed to the said microphone from symmetrical directions, in order to automate the measurement, to reduce cycle time measurements and maintenance personnel, the signal taken from the microphone when applying an acoustic signal to the latter from one of the tested directions is normalized using a coefficient controller before The signal to the strictly defined level corresponding to the measuring instrument is 100% or 1, and the signal taken from the microphone when the acoustic signal is fed from the second test direction j is fed to the measuring device with the same transmission ratio of the electrical path that and at the signal from the first direction, and read; the symmetry value directly from the indicator of the measuring device, calibrated accordingly.

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i J - LJ