| 摘要 |
PURPOSE:To establish filters of high accuracy without adjustment, by giving the variable control type bias magnetic field applying means with the non-crystal magnetostriction thin plate of the conductive constituent. CONSTITUTION:When high frequency current is flown to the first zigzag type coil 2, the magnetic field superimposing the AC magnetic field and the magnetic field by the first DC bias applying means 3 is fed to the non-crystal magnetostriction thin plate 1. The high frequency current inputted is Fourier-transformed into oulse train. Although this pulse train reaches the second zigzag type coil 2' and the sound absorbing body 4 in the non-crystal magnetostriction thin plate 1, the pulse train reached the second zigzag type coil 2' is converted again into electric signal with the Biraly effect. The center frequencies f01 11 and f02 of the filters F01 and F02 are in proportional to the sound speed of the non-crystal magneto striction thin plate 1. The sound speed of the non-crystal magnetostriction thin plate 1. The sound speed of the non-crystal magnetostriction thin plate is greatly changed with the magnetic field. |
