TRANSIENT PROCESSES IN THE PLL LOOP FOR LARGE INITIAL FREQUENCY DETUNINGS

In the processing and generation of radio signals, a phase locked loop is widely used. When processing signals in demodulators, the carrier wave synchronization and clock synchronization are carried out. The range-quartz frequency stabilization is carried out by digital frequency synthesizers, built on the basis of phase locked loop with programmable digital frequency dividers. Under the conditions of formation of reference sinusoidal oscillations, it is usually necessary to obtain a low level of non-harmonic discrete spectral components localized near the carrier. These secondary components are caused by pulsations of the control voltage of the impulse-phase detector of the phase locked loop system operating in the time-sampling mode. The suppression of these spectral components is carried out by including high-order low pass filters in the phase locked loop circuit. The use of such filters in the tracking demodulators increases their selectivity along the adjacent channel. In this case, there are problems with ensuring the stability of the system in the "small" and "big”. The paper considers the work of phase locked loop, which has the property of self-organization and ensures a rapid recovery of the synchronization regime for large perturbations. This system includes a binomial low pass filter that suppresses by products of frequency synthesis and increases the selectivity of demodulators along the adjacent channel. The paper shows that this system with binomial low pass filters, including the 5th order, can satisfy the stability criterion in "big" under certain conditions. Modeling of the phase locked loop system, which has the property of self-organization and with high-order binomial low pass filters included in its composition, has shown that the processes in it are stable at large initial detuning in frequency. The duration of the transient processes is proportional to the magnitude of the detuning in frequency. On the basis of the obtained results, it can be asserted that the considered phase system provides an extension of the functionality in the processing and generation of radio signals.

1. Pasternak G., Whalin R.L. Analysis and synthesis of a digital phase-locked loop for FM demodulation // Bell Syst. Tech. J. 1968. Dec. PP. 97–105.

2. W.C. Lindsey. Synchronization Systems in Communication and Control, Englewood Cliffs: Prentice – Hall, 1972.

3. U. Mengali. Synchronization techniques for digital receivers/ Umberto Mengali and Aldo N. D’Andrea. Plenum Press, New York, 1997.

4. Yamamoto H., Mori S. Performance of a binary quantized all digital phaselocked loop with a new class of sequential filter // IEEE Trans. 1978. Vol. Com-26. No 1. PP. 35–45.

5. Levin V.A., Malinovskij V.N., Romanov S.K. Sintezatory chastot s sistemoj impul'sno - fazovoj avtopodstrojki [Frequency synthesizers with a pulsesystem PLL] . M.: Radio i svyaz'. 1989. (in Russian)

6. Gelozhe YU.A., Klimenko P.P. Upravlenie processami v nelinejnyh sistemah [Process control in nonlinear systems]. M.: Radio i svyaz', 2006. (in Russian)

7. Su D., Meyer A. Modern theory of automatic control and its application. Moscow: Mechanical engineering, 1972.

8. A.s.484617 (USSR) Ustrojstvo IFAPCH [System PLL] / Gelozhe Yu.A. 1975. Byul. No 34. (in Russian)

9. A.s.987818 (USSR) Sintezator chastot [Frequency Synthesizer]/ Gelozhe Yu.A. 1977. Byul.No.1. (in Russian)

10. Геложе Ю.А., Клименко П.П. Системы фазовой автоподстройки частоты с ФНЧ высоких порядков // Радиосистемы. Радиолокационные устройства и системы управления, локации и связи. 2004. Вып. 78.