Signal voltage limiting circuit - has comparator for signal voltage for comparing with two voltage thresholds, defining voltage window

摘要

The signal voltage is applied to a high-ohmic load, such as an amplifier input, via a coupling capacitor as a.c. coupling. The signal voltage is compared with two voltage thresholds, defining a voltage window. When the signal voltage lies outside the voltage window, a shifting current is fed to the capacitor via a load-side circuit node, with the current shifting the signal voltage back into the voltage window. Pref. the shifting current is approx. constant and is oppositely polarised for exceeding or non-reaching the both different voltage thresholds. Typically two comparators (K1,2) are used in a specified circuit arrangement w.r.t. the circuit node (A). ADVANTAGE - Facility for evaluating lowest signal portions even with level limiting of a signal voltage.