The paper mainly concerns interference measurement in spread spectrum, wireless communication systems. A new digital signal-processing method is proposed, which proves non intrusive and independent of the specific system considered. Thanks to the nice properties of the wavelet packet transform, the method is capable of extracting the occurred interference from the spread spectrum signal, thus ensuring accurate interference magnitude and frequency estimates also in critical conditions: interference level much smaller than that characterizing the spread spectrum signal, and interference spectral content very close to the carrier centre frequency of the considered system.

In this paper, an incremental Analog-to-Digital Converter (ADC) designed as part of the signal-conditioning circuitry for tissue impedance measurement system is presented. Continuous-time design techniques has been used and a modified implementation of the conversion algorithm, with respect to its discrete-time counterpart, has been developed. To reduce the influence of the no-idealities, analog and digital corrections have been also implemented. A prototype in 0.8 µm CMOS technology has been fabricated and tested. Experimental results are reported.

Remote, wireless controlling of distributed virtual instrument (DVI) using GSM mobile phones is considered. Interactive WAP service is applied to configure measuring system, to control measurement process and to access to measurement data. The service is based on ASP technology and dynamic databases. National Instruments PC-1200 DAQ card, programmed with LabVIEW, was applied to design a wireless DVI (WDVI).

Quality of power sources is mainly increased by using better components and tricky electronic circuits. The paper introduces a control loop, which is similar to that used for the active cancellation of acoustic noise signals. In the feedback loop, the distortions of the signal are estimated by a combination of an adaptive Fourier analyzer and a resonator-based observer. Only the distortions should be compensated, therefore the actuator signal has low power. The paper introduces the active distortion reduction system and presents practical results, as well.

A solution for uniquely identifying any sensor connected to an evaluation unit without direct electrical connection to the existing measurement line is presented. The proposed solution is compatible with existing measurement systems, operates completely passive, and withstands temperatures up to 400°C as well as shocks up to 3500 g. The identification tag itself, which carries a unique serial number, is realized by a high-temperature stable surface acoustic wave (SAW) device. A low-cost radio frequency (RF) interrogation unit, which shares the existing sensor cable, is used for reading the sensor identification number.