| 摘要 |
PURPOSE:To constitute a small-sized, lightweight FM modulator with high efficiency and high performance, and the improve its versatility by using a ram wave device and propagating a ram wave in a piezoelectric substrate as an acoustic wave. CONSTITUTION:The ram wave device 10 has flat plate type electrodes 14 and 14' in the center of the across the piezoelectric substrate 12 whose thickness is smaller than propagation wavelength and two reed screen type electrodes 16 and 18 installed at distance across the electrode 14. An amplifier circuit 20 amplifies the electric output of the electrode 18 and feeds the result back to the electrode 16. A modulating signal is supplied between the electrodes 14 and 14' to obtain a modulated signal at the output of the circuit 20, so that small-sized, lightweight device with high efficiency and high performance is obtained and its versatility is improved. |
