A.R. Tagilaev, M.D. Isaev, Z.N. Mirzaev

Basic quantities of the balancing modulator is: losses of transformation, factor of suppression of carrying frequency, an outcome between signal inputs, a level of input signals (URF, UIF), a level of collateral components of a target signal. For today existing DSB do not provide demanded values of suppression of carrying frequency in a working range not less 60 dB and outcomes between RF signal inputs (RF, IF) not less 35 dB. As the reason for this to serve amplitude identity and the phase error (delay) of signals at conversion beating envelope through zero caused by presence RF of transformers i.e. asymmetry of arms of transformers as the phase of high-frequency filling with jump should changes on 180 degrees. The purpose of article - consideration of a way of formation of balancing modulation on the basis of switching phase RF of a signal. Principle of operation considered DSB it is based on switching of phase RF of a signal. The entrance signal of carrying frequency VHF of a range come on an input of an antiphase divider. The divider entrance RF divides a signal on two parts: equal on amplitude and 0 on phase 0 and 180 degrees. RF signals shifted on 180 degrees come on two inputs RF of the switchboard which the signal of switching of the form «meander» operates. Further the signal from an output of high frequency of the commutator come on an input of the mixer on which as the modulating signal in the form of sequence of half wave of a harmonious signal comes. The signal of commutation of high frequency of the commutator and modulating signal are synchronized. Depending on frequency of following of half wave of a modulating signal, the phase of high frequency of a signal on an output of high frequency of the commutator will be will change at 0 and 180 degrees. Exact commutation of a phase of a signal on an output of high frequency of the commutator allows to compensate a phase error of a signal in the mixer, at transition conversion beating envelope through zero as function cos (Ωt+Ф0) has different marks at the left and to the right of zero. As a result we receive a signal with two lateral harmonics suppressed carrying frequency and parasitic spectral components. Measured on the analyzer of networks ZVL of manufacture RODE &SCHWARZ carrying frequency, be from lateral harmonics with on frequency of a modulating signal shows a spectrum, that, is suppressed more than on 60 дБ. Losses of transformation thus makes 12,38 дБ. Experimental researches of breadboard model DSB are led in bandwidth of frequencies 30300МГц. Similar suppression of carrying frequency in a spectrum is observed in all bandwidth of operating frequencies. Thus, the offered method of formation of the balancing modulation, based on commutation of a phase of high frequency of a signal allows to provide: high suppression of carrying frequency, an isolation between the signal inputs, admissible losses of transformation. Application DSB, the formation of the balancing modulation realized on an offered method, in a navigating radio beacon to allow to provide high and stable depth of an amplitude modulation. Questions of realization DSB in a range of centimeter waves, on the basis of the given way, will be considered in the subsequent publications.