Yu. I. Sharapov

Four transformations with lowering input signal-s frequency are considered. These transformations use the first harmonics of a signal and the second and the third harmonics of the heterodyne for forming an intermediate frequency. They are compared with two classical transformations with lowering the input frequency, where an intermediate frequency is represented as a difference of signal-s and heterodyne-s frequencies. The comparison is realized with respect to the maximum admissible for using input frequency range, at which harmonic and combination components of given and lower orders are absent in the pass band. The goal of the investigation is to find transformations permitting the work at more wide input frequency ranges in comparison with classical transformations. Transformations with using signal-s and heterodyne-s harmonics can be applied at constructing frequency synthesizers and at signal receiving. Microelectronics possibilities allow obtain of mixing elements with pre-given characteristics ensuring the decrease of the transform coefficient at similar frequency transformations. Consideration of frequency transformations is realized with using the analytical computation method which allows investigation of transformations at varying signal frequencies and at reconfigurable or constant heterodyne frequencies for two types of mixers. Physical and mathematical essence of the method and its foundations are shown. Results of consideration of all transformations are written in table form to simplify their comparison and evaluation. It is shown that except classical frequency transformations other transformations with similar parameters exist.