is a waveform diagram illustrating the effect of errors in frequency doubler circuits that necessitates correction, such as by using an integrator and feedback. [0227]FIG. 34 is a circuit schematic illustrating a frequency doubler circuit that employs an integrator and feedback to solve the problem illustrated in FIG. 33. [0228]FIG. 35 is a waveform diagram illustrating input and output waves cre