A Modulator Producing Pulses of 10-7Second Duration at a 1-Mc Recurrence Frequency

The development of a pulse generator and a modulator which will produce pulses of 10
^-7
second duration and 3,000-volt amplitude at a 1-Mc recurrence frequency is described. The modulator is developed for the special case of a nonlinear load impedance consisting of 125 μμf capacitance for the leading half of the pulse and a spark discharge for the trailing half. The high recurrence frequency gives rise to problems not generally encountered in the design of pulse circuits. Other applications, such as the second modulation of a high-recurrence-frequency pulsed carrier with voice frequencies, suggest themselves. A new pulse-generating circuit, capable of producing positive pulses whose duration is one-tenth the period of the 1-Mc input sine wave, is developed. This pulse generator can be operated at moderate power levels sufficient to drive the modulator.