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一、关于分贝“分贝”这一词,在超声检验中经常用到。其意义如下:设J_1、J_2表示两个不同声强度,取J_1/J_2的常用对数,定义贝尔数=1_0gJ_1/J_2 (贝尔)贝尔这单位,实用中感到太大,故常用另一较小单位叫分贝,常以db或dB表示。定义: 贝尔数=10logJ_1/J_2 (db) (1)可见1分贝=1/10贝尔用A、A_2表示两不同声压。因声强度与声压的平方成正比(声阻抗一定),故由(1)式有:
First, on the decibel “decibel” this term, often used in ultrasonic testing. Its significance is as follows: Let J_1, J_2 represent two different acoustic intensities, take J_1 / J_2 common logarithm, define the Bell = 1_0gJ_1 / J_2 (Bell) Bell this unit, practical too much, so commonly used another smaller The unit is called db, often db or dB said. Definition: The number of Bells = 10logJ_1 / J_2 (db) (1) shows that 1 dB = 1/10 Bell uses A and A_2 to represent two different sound pressures. Because of the sound intensity and sound pressure proportional to the square (acoustic impedance must), so by (1) type: