Abstract <p>Harmonic signal frequency multipliers allow attaining stable high-frequency oscillations at a relatively low frequency of the reference generator’s output signal. The existing harmonic signal frequency multipliers have a low speed, low efficiency, a high level of side harmonics, and a limited range of operating frequencies. In this study, the principles of construction and operation of harmonic signal frequency multipliers, as well as their main disadvantages and applications, are described. A new principle of multiplying the frequency of the sinusoidal voltage is proposed, based on the regulation of the input signal phase within 360° by a phase shifter controlled by an alternating sawtooth voltage whose amplitude is equal to the input signal’s amplitude. The development and research of frequency multipliers implementing the proposed principle are carried out by methods of structural design and mathematical modeling. The results of the development of the doubler and tripler of the harmonic frequency, which perform better than the known ones and operate on the basis of the proposed principle, are presented. Their structural schemes are provided. Simulation models of the frequency multipliers under consideration were compiled in the Matlab &amp; Simulink environment and oscillograms of their operation are obtained, confirming their operability and the correctness of the choice of technical solutions. A fast controlled frequency multiplier is developed, having a low level of side harmonics, a wide range of operating frequencies, and an adjustable multiplication factor, including its fractional values. It is demonstrated that the multiplication factor of the developed harmonic signal frequency multipliers can reach double-digit values several dozen.</p>