a pulse shaper has a periodically reversible capacitor for pulse shaping . in performing testing of electronic components , the test specimens must be driven with different or , respectively , variable pulses . to this end , the pulse shaper has two mutually symmetrical circuits serving for the periodic charging and discharging of the capacitor , the circuits respectively containing binarilly switched adjustable resistors for setting the rise time and fall time of the pulse edges of the pulses to be formed , as well as containing a current source and a voltage source for the proportional change of the edge steepness with respect to the change of the shift of the pulses . in addition , voltage limitation is provided to generate the desired amplitude shift with respect to the baseline voltage with structure assigned to each circuit , the bias voltage sources of such structure being variable as a function of the shift to be set . the charging and discharging occurs by way of a periodically switched differential switch respectively comprising two transistors . the pulse shaper of the invention is particularly suited for automatic testing units for data processing devices .