Eugenio J. Tacconi

Complementary rules to Ziegler and Nichols' rules for a regulating and tracking controller

Abstract Traditionally, PID controllers are designed either as regulating or as tracking controllers because, usually, it is not possible to fulfil both functions simultaneously. Designing rules complementary to Ziegler and Nichols ones are introduced. They allow, using a special connection of the classical PID, the tracking behaviour to be improved without modifying the regulating characteristics.

Noise power estimation and overlapped signals detection

Abstract In order to detect a deterministic signal in nonstationary Gaussian noise with power fluctuations and obtain a constant false alarm rate, a classical matched filter receiver normalized by an optimal noise alone reference (NAR) power estimator is used. For the case of overlapped signals, the matched filter characteristic of providing a maximum likelihood estimate of arrival times and signal amplitudes, is lost. The NAR property of the power estimation is at the same time strongly degraded. In this paper a realizable inverse filter of the received signal is derived. By using this filter a high resolution of superposed signals is obtained. Besides, the noise power estimation at the inverse filter output posses the interesting NAR property, even in presence of overlapped signals.

Huffman sequences with uniform time energy distribution

Abstract In this work, the generation of Huffman sequences with a given length and uniform time energy distribution is analyzed and a systematic method for designing the sequence is presented. The comparative analysis with a uniformly distributed pseudorandom signal shows the advantages of the proposed Huffman sequence.

Inverse filtering approach for improving sonar signal resolution and amplitude estimation

Abstract The characteristics of classical matched filter receivers are strongly degraded in the presence of overlapped sonar signals. An inverse filtering approach for improving signal resolution is presented in this paper. Non-causal interpolation at the inverse filter output improves the estimation of the signal amplitude even in the presence of overlapped sonar signals.

Noise power estimation insensitive to overlapped sonar signals

Abstract In order to detect a sonar deterministic signal in nonstationary noise with power fluctuations and obtain a constant false alarm rate, an automatic gain control system is generally used at the input of the matched filter. Usually, however, this filter does not differentiate between signal and noise and in general limits the amplitudes of strong signals. In this paper, an inverse filter is used to obtain a noise power estimation possessing the interesting noise alone reference property, even in the presence of overlapped sonar signals. The proposed noise power estimation is compared with the known best ‘noise alone reference property’ power estimator for nonoverlapped signals.

Improved detection in sonar and radar by using phase signals

Abstract The shape of the transmitted pulse plays an important role in active sonar and radar applications. The advantage of using phase signals for detecting overlapped signals in nonstationary additive noise is analyzed in this work. Approximate phase signals are constructed by means of finite-time sequences having good time-energy distribution. The properties of the phase signals lead to the development of a noise-power estimator insensitive to the presence of overlapped signals. The estimator bias when using approximated phase signals is calculated.

Adaptive Control for Systems With Time-Delay

Abstract Works on Smith and analytical predictors have been widely reported; however this, adaptive techniques are not considered in most of them. A modification to the generalized analytical predictor, more suitable for the use of on-line adaptive control is presented. The method has been applied to the control of an electrical oven and the experimental results are shown.