| 摘要 |
An acoustic filter according to an embodiment of the present invention comprises a signal input port, a ladder-type filter circuit, a first-quarter ladder-type filter circuit, a second-quarter ladder-type filter circuit, and a signal output port. The first-quarter ladder-type filter circuit and the second-quarter ladder-type filter circuit are connected in parallel, the signal input port is connected to the ladder-type filter circuit, the ladder-type filter circuit is connected in series to the two quarter ladder-type filter circuits connected in parallel, and the two quarter ladder-type filter circuits connected in parallel are connected to the signal output port. Here, a C-axis direction of resonators in the first-quarter ladder-type filter circuit is the opposite to a C-axis direction of corresponding resonators in the second-quarter ladder-type filter circuit. |
