| 摘要 |
A differential switched capacitor filter section which comprises a differential amplifier (OTA), a first set of switched capacitors (C11, C12) coupled between a non-inverting output (+) and an inverting input (-) of the differential amplifier (OTA), and a second set of switched capacitors (C21, C22) coupled between an inverting output (-) and a non-inverting input (+) of the differential amplifier (OTA). In the sets of switched capacitors (C11, C12; C21, C22), first terminals of the capacitors are coupled to a corresponding one of the outputs (+; -) of the differential amplifier (OTA) thru first switches (S1.11, S1.12; S1.21, S1.22), and to one of the differential inputs (Vin+; Vin-) of the filter section thru second switches (S2.11, S2.12; S2.21, S2.22). Second terminals of the capacitors are coupled to a corresponding one of the inputs (-, +) of the differential amplifier (OTA) thru third switches (S3.11, S3.12; S3.21, S3.22), and to a reference terminal thru fourth switches (S4.11, S4.12; S4.21, S4.22). Within each set, corresponding switches operate at mutually differing switching phases ( phi 1; phi 2).
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