Abstract:
A system for detecting distances, usable, for instance, in the vehicle sector or in robotics applications, comprises at least one transducer (16), such as a piezoelectric transducer, for generating a transmission signal to be sent in the direction of an obstacle (O) and for obtaining a receiving signal corresponding to an echo produced by the reflection of said transmission signal off the obstacle (O). The transducer (16) is driven by a chaos generator (10), such as a Chua's circuit (10). The system preferably comprises a correlator (18) for correlating the transmission signal (TX) and the receiving signal (RX) so that the distance between the obstacle and the transducer (16) is identified by the instant at which the aforesaid correlation assumes the maximum value. Preferably, the transmission signal (TX) is a square-wave signal selectively generated with one first frequency and one second frequency, the jumps between said two frequencies being determined by the instants of emission of the pulses (CPPM) generated by a pulse generator of an analog type (12) driven by the chaos generator (10).
Abstract:
A chaotic-signal generator comprises a set of elements (1 to 4) for generating signals, which are connected together according to a scheme of chaotic dynamics of signal generation. The connection scheme may advantageously correspond to the circuit generally referred to as Chua's circuit, in particular in its possible implementation as a cellular neural network (CNN). Interposed in the aforementioned connection scheme is at least one switch (5), such as a MOS transistor, the opening and closing of which causes the variation in the chaotic dynamics of signal generation. The opening and closing command signal (u(t)) applied to the aforesaid switch (5) may therefore be made to correspond to a modulating signal in view of transmission on a channel, such as a high-noise channel. In a particularly preferred application, the aforementioned modulating signal is a binary signal, and the aforementioned opening and closing command signal is constituted by a switching signal, the switching frequency of which is caused respectively to increase or decrease depending on the logic level assumed by the modulating signal.