| 摘要 |
An electronic sample-and-hold circuit (10, 24) of the type which includes a correction network is designed to eliminate a primary signal feedback loop. A correction capacitor, (CC), a coupling capacitor (CCC), and a primary holding capacitor (CH) are connected in series, respectively, between two ground points. The common node of the coupling capacitor and the holding capacitor is a held signal node (12). The common node of the coupling capacitor (CCC) and the correction capacitor (CC) is a correction voltage node (20). The circuit output is from the signal node (12) through a buffer (14) and a stage selecting switch (SF). The output is fed back to an operational amplifier (18, 26) which has its output connected to the correction node (20) through a correction sampling switch (SC). A switched (SA) feedback loop connects the output of the amplifier 18 to the inverting input port. The primary signal input (IN) is to the signal node (12) through a primary sampling switch (SS). The noninverting input (+) of the amplifier (26) is connected to the output of a buffer (22). The input of the buffer (22) receives the input signal through an input switch (SI) and is also connected to an input capacitor (CI), which has its other side grounded. Also disclosed is a circuit (24) in which the operational amplifier (26) is a less complex, inverting amplifier provided with a switched (SA) local bypass loop.
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