Abstract: A highpass feedback loop for A.C. coupled amplifier circuits is disclosed, by means of which pulse undershoot recovery is accelerated. The feedback loop includes an operational amplifier which goes into limiting above a selected amplitude threshold so that for pulses exceeding the threshold the amplifier frequency response is unaffected.

Abstract: A source of pulse waves is coupled to a first transmission line and a second transmission line, the inputs of each line being parallely coupled. The input of the first line is in series with its characteristic impedance. The outputs of each line are series coupled for summation of the output voltage of each line. The first line develops a voltage having a opposite polarity of the voltage of the applied signals. Summation of the output voltages of the two lines effects the required cancellation for pulse waves having a pulse width larger than the difference between the time delay of each line. A device for utilizing the pulses is connected between one output of the first transmission delay line the grounded output of the second transmission line.