| 摘要 |
A detector for sensing or measuring objects passing a measurement path (5) has a detection element (6), the output signal of which is a function of objects discovered in the measurement path. Said output signal is fed to an amplifier and filter circuit (7 - 9), the output of which is connected to two parallel integration circuits (11, 12). The integration circuits have time constants ( tau SH, tau L) of different magnitudes, and their output signals are fed to a comparator (13) for obtaining an operative signal indicating the presence of an object in the measurement path, this signal being unresponsive to long-duration fluctuations in the detector's operating conditions, e.g. dirtying of the detection element. |
