Resonator, delta-sigma modulator, and wireless communication device

摘要

Two T filters, one of which includes two resistive elements and one capacitive element and the other of which includes two capacitive elements and one resistive element, are inserted in a negative-feedback section of an operational amplifier, and a resistive element and a capacitive element are connected between each of intermediate nodes and a signal input terminal. A resistive element and a capacitive element which are connected to each other in parallel are connected between the signal input terminal and an inverting input terminal of the operational amplifier. With this configuration, overall admittances where elements connected to the corresponding intermediate nodes are in parallel connection are equal to each other.

主权项

1. A resonator comprising:
an operational amplifier; a first resistive element connected between a first node and an inverting input terminal of the operational amplifier; a second resistive element connected between the first node and a non-inverting output terminal of the operational amplifier; a first capacitive element connected between a second node and the inverting input terminal of the operational amplifier; a second capacitive element connected between the second node and the non-inverting output terminal of the operational amplifier; a third capacitive element connected between the first node and a third node; a third resistive element connected between the second node and the third node; a fourth resistive element connected between the first node and a signal input terminal; and a fifth capacitive element connected between the signal input terminal and the inverting input terminal of the operational amplifier, wherein an overall admittance where elements connected to the first node are in parallel connection is equal to an overall admittance where elements connected to the second node are in parallel connection.