| 摘要 |
PURPOSE:To increase the eliminating performance of a disturbing wave as well as the sensitivity of a receiver, by using a surface acoustic wave amplifier for a filter of the receiver. CONSTITUTION:The signal supplied from a matching circuit 15 is applied to an input means 121 of a surface acoustic wave amplifier 12 and then converted into a surface wave signal. This surface wave signal is transmitted to an output means 122 through the surface part of a piezoelectric body I. In this case, the bias DC voltage given from a DC power supply 13 plus the pump electric power of frequency 2f supplied from a high frequency power supply 14 are supplied to an electrode M1 on the body I. As a result, the surface wave signal is amplified by a parametric interaction due to the capacitance nonlinearity of a surface charge layer at a display part of a semiconductor substrate S provided at the lower part of the electrode M1. Then the amplified surface wave signal is extracted via the means 122. The output of a matching circuit 16 is supplied to an IF signal filter 7 via a frequency converter 5. |
