| 摘要 |
A circuit for removing unwanted temporal portions of a voltage varying signal on the occurrence of a reset signal and for differentiating a resultant corrected signal with respect to a reference voltage, has a switch (SW) responsive to the reset signal applied to a first input. The switch is responsive to the reset signal to divert a second input of the switch to a second output from a first output and thence to return the second input to the first output. An input capacitor (C1) receives the input signal. A first operational amplifier (U1-B) has positive and negative inputs and an output connected to the second input of switch (SW), the positive input being connected to receive a voltage representative of the current through the input capacitor (C1). A storage capacitor (C5) has one side connected to a reference voltage and has its other side in electrical connection to the negative input of the first operational amplifier (U1-B) and the first output of the switch (SW). An inverting amplifier (U2) is connected to receive the second output of the switch (SW). A second operational amplifier (U1-A) receives the corrected signal from the inverting amplifier (U2) and has a negative input which is connected through a first resistor (R3) and through the inverting amplifier (U2) to the second output of the switch (SW). The negative input of the second operational amplifier is also in electrical connection through the first resistor (R3) with the input capacitor (C1) and with the positive input of the first operational amplifier (U1-B). A positive input of the second operational amplifier is connected to a reference voltage, and provides a differentiated corrected signal at its output which is connected via a feedback resistor (R4) to the negative input. |
