Frequency multiplier including grid having plural segments

Apparatus for multiplying the frequency of an AC signal by a factor N, where N is an integer greater than one, comprising an electron tube including a cathode for emitting an electron beam, a grid including N segments in proximity to the cathode and positioned to be responsive to the beam emitted by the cathode, the grid being electrically biased and electrically coupled to the signal for causing the beam to be configured as N groups of electron bunches during each cycle of the signal so that each of the segments accelerates one group of said N groups of electron bunches for a duration of about 1/N th of each cycle of the signal, different groups of said N groups of electron bunches associated with the different segments being accelerated at phases displaced from each other during each cycle of the signal, and means responsive to the N groups of bunches for deriving an output signal having a frequency N times that of the signal.