Assignment of the inductance Q-factor is given by the determination of equivalent circuit parameters of the measured inductor or the Q-standard. In case of serial equivalent circuit, values of the inductance LS and the resistance RS have to be evaluated. Conventional precious bridges routine used for inductance and resistance measurements typically work up to some hundreds of kHz. For higher frequency ranges these methods are not available to apply for finding both parameters inductance LS and resistance RS.
This paper describes a method based on utilizing resonance technique for inductance Q-factor measurement. The measured inductor and auxiliary capacitor form the resonance circuit. Impedance of this circuit is measured by means of an impedance analyser in suitable wide frequency range around the desired frequency. Subsequently mathematical data processing is applied to improve results obtained from the impedance analyser. This method has been developed for calibration of Q-standards designed for ultra-acoustic frequency range (typically hundreds of kHz up to tens of MHz).

The paper compares six methods of measurement of the phase difference of low frequency distorted sinusoidal digitized signals corrupted by additive noise. Influence of SNR, THD, signal DC offset, ADC resolution, ADC range use, and number of samples per signal period can be investigated and presented in graphical form by means of the program written in MATLAB environment. The investigated methods are two modifications of classical zero-crossing based measurement, DFT based measurement, usage of phase-sensitive rectifier and two modifications of sine-wave fit algorithm. Selected results of both simulations and measurements are presented.

The paper presents a practical approach to ion selective electrodes (ISE). The behaviour of Pb⁺² ISE (ELIT8231) and Cd⁺² ISE (ELIT8241) for pure (only Cd⁺² or Pb⁺²) and mixed solutions (Cd⁺² and Pb⁺²) in static and dynamic conditions is studied. The pH variation of ISE test solution is considered in order to perform the pH correction of the ISE potentiometric selectivity coefficient determined under static conditions using a neural network processing structure. The dynamic test is performed in order to evaluate sensor’s transient response and time constant as well as ion interference and pH influence on sensor’s output. The experimental set-up is expressed by a multisensor virtual measurement system that acquires the voltage of the sensor channels, controls the ISE dynamic test and performs the data processing using a software implemented in LabVIEW.

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.

This paper reports the implementation of a sensing and alarm integrated system connected through the Transducer Independent Interface (TII) to a Network Capable Application Processor (NCAP), emulated in a PC. The “Correction Engine” and the calibration features of the NCAP are used to process the data acquired via the transducer and also to add auto range capabilities to the conditioning circuits of the input quantities. The NCAP is also used to establish the interface with the Internet. A working prototype is developed for water quality monitoring with pH and temperature sensors and with an alarm to detect values outside a pre-defined range.