| 摘要 |
PROBLEM TO BE SOLVED: To produce a demodulation signal of a proper integrated waveform by connecting a circuit element of variable inductance in series to the output comb-line electrode of a surface acoustic wave element and suppressing the variance of the delay value. SOLUTION: An example of a surface acoustic wave matched filter is shown in the diagram. A circuit element 3 of fixed inductance which resonates by the capacitance and carrier frequency of a signal input encoding electrode 5 is connected as a matching circuit of the electrode 5. A circuit element 1 of variable inductance is connected to an output comb-line electrode 6. In such a constitution, the variance of matching points caused by the variance of capacity of the electrode 6, the variance of accuracy of inductance, the variance due to the assembly, etc., can all be suppressed. Furthermore, the reactance component can be set at zero at the matching points. As a result, the reflection coefficient is reduced, and the output voltage is increased. |
