| 摘要 |
<p>A switched-capacitor circuit for passing an audio frequency over a predetermined range of frequencies fabricated on a monolithic semiconductor substrate is provided. The switched-capacitor filter includes a first amplifier and a second amplifier. A first integrator capacitor is interconnected to the first amplifier. A second integrator capacitor is interconnected to the first amplifier. A first input switched-capacitor is interconnected between the first amplifier and the second amplifier, such that the first input switched-capacitor samples and holds the output of the second amplifier during a first clock phase thereby isolating the output of the second amplifier from the input of the first amplifier. During a second clock phase the first input switchedcapacitor applies the output of the second amplifier to the first integrator capacitor. A second input switchedcapacitor is provided and is interconnected between the output of the first amplifier and the input of the second amplifier, such that during the second clock phase the second input switched-capacitor applies the output of the first amplifier to the second integrator capacitor. The switched-capacitor circuit functions such that effectively zero phase shift is introduced into the signal being processed by the switched-capacitor circuit.</p> |
