| 摘要 |
PURPOSE:To widely change the variable frequency range and to improve the selectivity Q, by providing a reflection electrode near a surface acoustic wave transducer and reflecting the selected frequency component. CONSTITUTION:An insulation film 6 is formed on a semiconductor substrate 7 and signal input and output transducers 1, 2 are formed on a piezoelectic element attached with a piezoelectric film 5 on the film 6, and pump electrodes 3, 4 are formed near the transducers 1 and 2. A DC bias is applied to the pump electrodes 3, 4 and a pump voltage in frequency 25, twice the selected desired frequency (f) is applied. When an input electric signal is applied to the input transducer 1, the signal is converted into a surface acoustic wave signal for the propagation left and right, and when the component in frequency (f) propagates the pump electrodes 3 and 4, the component is amplified with parametric mutual operation and reflected at the same time and converted into the electric signal again with the output transducer 2. |
