Analog Replicator of Long Chaotic Radio Pulses for Coherent Processing

The relative structural simplicity of chaotic oscillators and the possibility of obtaining signals with a large dimension is of great interest for wireless data transmission and processing. The diversity of signal waveforms from the same source of chaos is provided by a fundamental property of chaotic oscillations: sensitivity to the choice of initial conditions. In this paper, this sensitivity is employed in the proposed method for forming analog chaotic radio pulses of arbitrary (specified) duration using an analog oscillator in such a way that the pulse shape can be changed and repeated from pulse to pulse. To repeat the shape of oscillations for an arbitrarily long period of time is not a problem for digital chaotic oscillators, but for analog systems, this is a challenge due to the impossibility of controlling the initial conditions and the evolution of the analog trajectory. In this paper, a new method for generating chaos is proposed, which can both change and repeat the shape of a chaotic signal of arbitrary duration, i.e., long chaotic radio pulses. The generator acts as a reservoir and as a replicator from which, under external influence, a signal of a certain shape can be extracted, and this shape can be reproduced. The term “long” in this case means that the duration of chaotic radio pulses is many times greater than the characteristic time of divergence of chaotic trajectories. To prove the correctness of the proposed generation method, the results of its experimental implementation in the frequency range of 100 to 500 MHz are given. Examples of forming equal pulses with a duration of about 20 to 200 quasi-periods of oscillations (up to 500 ns) are given. The proposed method provides the technical possibility of forming pulses whose dimensions can vary in a wide range, which is important for implementing large processing gains in various wireless applications. The method can be implemented in various frequency ranges in the class of analog generators of chaotic oscillations, since the employed generation method, i.e., modulation of a transistor generator by supply voltage, is natural for radio engineering.