İhsan PEHLİVAN, Ünal ÇAVUŞOĞLU, Yılmaz UYAROĞLU

SÜREKLİ ZAMANLI OTONOM KAOTİK DEVRE TASARIMI VE SİNYAL GİZLEME UYGULAMASI

Kaos ve kaotik sistemler birçok uygulama alanına sahiptir. Uygulama alanlarından biri de kaos ile güvenilir haberleşmedir. Kaotik işaretler, başlangıç şartlarına hassas bağımlıdırlar. Kaos tabanlı güvenilir haberleşme sistemleri, iletilecek bilgi işaretlerinin spektrumunu geniş bir sahaya yayabilmeleri, eşzamanlı olarak bildiri işaretlerini kodlayabilmeleri ve bu işlemleri basit ve pahalı olmayan kaotik devre düzenekleriyle gerçekleştirebilmeleri sebebiyle, literatürdeki standart geniş spektrumlu haberleşme sistemlerine alternatif olmuşlardır. Bu çalışmada sürekli zamanlı otonom kaotik sistemlerin devre tasarımı, 1996 yılında tanıtılan doğrusal olmayan Thomas sistemi (TS_96) üzerinde anlatılmış, ayrıca Lorenz sistemi üzerinde de PSpice-tabanlı bir sinyal gizleme uygulaması örneği verilmiştir. TS_96 sisteminin kaotik denklemleri elde edilmiş, kaotik devresi tasarlanmış, hem PSpice ortamında simüle edilmiş hem de fiziksel olarak elektronik devresi devre tasarımı yapılmıştır. Kaotik sinyal gizleme uygulaması için, Lorenz sistemi ele alınmış, Matlab ortamında nümerik olarak ve PSpice ortamında elektronik devre simülasyonu gerçekleştirilmiştir.

DESIGN OF A CONTINUOUS-TIME AUTONOMOUS CHAOTIC CIRCUIT AND APPLICATION OF SIGNAL MASKING

Chaos and chaotic systems have many fields of applications. One of the popular practical applications is secure communication. Chaotic signals depend on initial conditions very sensitively. Chaos-based secure communication systems have been the alternative of the standard spread-spectrum systems, since they are able to spread the spectrum of the information signals and simultaneously encrypt the information signals with chaotic circuitry which is simple and inexpensive.In this study, the circuit design of the continuous time autonomous chaotic systems are explained in details based on nonlinear Thomas system(TS_96) which was introduced in 1996. In addition an example of the PSpice-based signal hiding implementation on the Lorenz system is given. The chaotic system equations of TS_96 are obtained, its chaotic circuit is designed, both its circuit design simulated in PSpice and is realized physically. For the signal hiding application with chaotic signal, the Lorenz system are considered, consequently its numerical simulations and electronical circuit simulations are realized in Matlab and PSpice environments.

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