| 摘要 |
A compact, DC-coupled Schmitt trigger circuit is disclosed for providing fast switching in response to differential current signals from an input source such as an amplifier. The circuit includes first and second matched pairs of transistors disposed for performing switching and feedback functions, respectively, and for producing a voltage at an input or base of the first pair equal to the sum (AND function) of the source voltage and the voltage at an emitter of the feedback pair. In response to the applied current signals, the transistors of the second matched pair are always in a conducting state (and requires no extra time to turn on) regardless of the conducting state of either of the transistors of the first matched pair. The circuit includes first and second matched pairs of resistors coupled to selected ones of the transistors, the resistance values of which second matched pair of resistors are selected such that the input impedance of the circuit peaks at a selected high frequency of the applied current signal.
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