| 摘要 |
<p>Apparatus is disclosed for performing analog computations and other analog signal conditioning with extremely high accuracy and zero DC offset. In one aspect a computational cell is described with includes first (20) and second (230) low-precision resistors each having a first and second terminal. A current is established in the first resistor through a closed-loop circuit (40,10) in which the first terminal (16) of the first resistor is connected to the second input of an error amplifier (40), and the first input of the error amplifier receives an input signal (vi1). During a second time period, the current is maintained in the first resistor. A new current is established in the second resistor through a feedback loop (40,224) in which the first input of the same error amplifier (40) is now connected to the first terminal (228) of the second resistor, while the first terminal (16) of the first resistor (20) remains connected to the second terminal of the error amplifier (40). By holding the second terminal of the first resistor at a V i2 voltage during the first time period and at a Vi3 voltage during the second time period, and by holding the second terminal of the second resistor at a Vi4 voltage during the second time period and at a Vi5 voltage during a third time period, the cell outputs (at the first terminal (228) of the second resistor) during the third time period a voltage V02 = Vi1 - Vi2 + Vi3 - Vi4 + Vi5. Extremely high accuracy analog memory apparatus is also disclosed.</p> |
