V.V. Afanasiev - Dr.Sc. (Eng.), Professor, Department of Radioelectronic and Quantum Devices, Kazan National Research Technical University named after A.N.Tupolev E-mail: vafv@reku.kstu-kai.ru E.R. Mardanshin - Post-graduate Student, Department of Radioelectronic and Quantum Devices, Kazan National Research Technical University named after A.N.Tupolev E-mail: m.emil89@mail.ru

Functionally-reject filters based on the principle of two-channel invariance theory will be effective in the application of for the selective suppression of narrowband interferers of known form but a priori unknown frequency. The functionally-reject filter (FRF) is limited to non-linear distortion of useful signals so these filters are used when possible selection of useful information at the emerging non-linear transformation of signals, for example in communication systems with a relative phase-shift keying. The objective is to develop recommendations and rationale for selection of FRF parameters for suppressing narrowband interference during processing phase modulation (FM) signals. Simulation and experimental study of interference suppression sine wave of FRF was held. A digital nonlinear functionally-reject filter with a frequency of sampling (N) from 300 to 400 provides suppression with coefficient Кп≤5∙103 narrowband interference in the form of a sinusoidal signal with a priori unknown frequency. Converting FM signals of FRF that suppresses narrowband interference has been investigated. The ability to determine the useful information at the output of FRF contained in the switching phase of the FM signal which is estimated as the ratio of the signal amplitude at the output of the filter and the standard deviation output noise signal on the output of the filter occurring due to sampling the FM signal has been evaluated. Selecting 1= π /2 provides an improvement in the signal / noise ratio at the output of the filter is not less than 25dB compared to 1= π.

 

1. Ivanova V.G., Semenov E.S., Tjazhev A.I. Rezhekcija sosredotochennojj po chastote pomekhi metodom vozvratnogo geterodinirovanija // Fizika volnovykh processov i radiotekhnicheskie sistemy. 2004. № 4. S. 100-108.
2. Afanasev V.V., Polskijj JU.E. Metody analiza, diagnostiki i upravlenija povedeniem nelinejjnykh ustrojjstv i sistem s fraktalnymi processami i khaoticheskojj dinamikojj: Monografija. Kazan: Izd-vo Kazan. gos. tekhn. un-ta. 2004. 219 s.
3. Mardanshin EH.R. Selektivnoe podavlenie signalov nelinejjnykh sistem. // Materialy Vseross. nauch. konf. molodykh uchenykh «NAUKA. TEKHNOLOGII. INNOVACII». V 4-kh chastjakh. Novosibirsk: Izd-vo NGTU. 2010. CH. 1. 365 s.
4. Afanasev V.V., Mardanshin EH.R. Cifrovye ustrojjstva selektivnojj funkcionalno-rezhektornojj filtracii signalov // Materialy XII Mezhdunar. Nauch.-tekhnich. konf. «Problemy tekhniki i tekhnologijj telekommunikacijj PTiTT-2011» (Kazan, 21-24 nojabrja 2011 g.). Kazan: Izd-vo Kazan. gos. tekhn. un-ta. 2011. S. 465-466.