Hot firings show that the frequency of the oscillating shock is close to the acoustic frequency. 熱試結果表明，振蕩激波的頻率與聲頻相近。
Using the acoustic noise signal generated by driving motor vehicles to vehicle classification is a new and promising method. 利用車(chē)輛行駛過(guò)程中所產(chǎn)生的聲頻噪聲信號進(jìn)行車(chē)型分類(lèi)是一種新方法，有較大應用前景。
Its frequency response has to be flat over the whole audio range. 它的頻率響應在整個(gè)音頻范圍內有所下降。
This paper introduces the principle and tested results of measuring nodulizing grade by audio frequency method. 介紹了音頻法檢測鑄件球化級別的原理及試驗結果。
