Because of their low zero drift chopper, dc amplifiers [I, pp. 22-23] are widely used in measuring equipment. The ratio of the maximum cut-off frequency of such an amplifier to its modulation frequency must be carefully chosen since an increase of its carrier frequency magnifies the effect of high-frequency pulse noise on the output voltage [2] in contactless modulators and shortens the useful life of contacting modulators. There is still no general agreement as to this matter. In [3], for instance, the authors recommend that the ratio of the modulation frequency to the maximum frequency of the amplified signal should be at least ten, while other publications, [4-6] for sinusoidal signals and [7] for signals of an arbitrary form, state that this ratio can be substantially lower.