Test pulse shaping circuit - has common collector transistor with bridging resistor reducing rise time of pulses

摘要

A digital circuit, suitable for connection between a test circuit and a cable connected to a circuit to be tested, reduces the rise time of the output pulse. It includes a transistor (T) connected in common collector configuration. Pulses for transmission by way of cable (K) are presented at a first input (E1). A control signal indicating whether the test circuit is connected to an input or output of the circuit under test, is fed to a second input (E2). The supply voltage is connected to the inputs via a resistor (R3) and two diodes (D1, D2). Under condition (E2=1, E1=1 the transistor (T) is conducting for the duration of the leading edge of positive pulses, bringing the pull-up resistor (R1), thereby increasing the slope of the pulses.