| 摘要 |
Apparatus for detecting slow and small changes of electrical signals including the sign of the changes, the apparatus includes: a controlled switch (2); a capacitor (3) charged to the voltage of a signal to be detected; an amplifier (5) for generating a pulse signal corresponding to the charge or discharge current of the capacitor (3) having corresponding proper sign; a window comparator (7) for indicating whether the output signal of the amplifier (5) lies in the range defined by the window or it has been crossed in negative or positive directions; storage and logic units each having first and second storage devices (8, 11); a pulse generator (9) connected to the controlled switch (2) to make.it closed for periodically repeated sampling periods; a first storage device storing the logical state of the window comparator (7) with proper sign, and a predetermined section of each pulse of the pulse generator reading such stored values of the first storage device into a second storaged device.
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