The power is the most important electromagnetic quantity from the metrological point of view, and for this reason the calibration techniques of high frequency power meters require a specific attention. Literature still refers to power meters of bolometer type, instruments that are mainly used almost only in the primary laboratories. Definitions, procedures, and calibration techniques elaborated for this instrument type must be adjusted before being applied to actual power meters, which work on different principles. Otherwise, inconsistent calibration results may be produced. This paper is aimed to ease the work of the laboratories that perform power meter calibrations from dc to 50 GHz, by elaborating on some technical aspect not well considered in the specialized literature.

In the paper, the design and implementation of a high-performance real-time power quality measuring instrument based on digital signal processor (DSP) is discussed. After the hardware and firmware instrument description, the paper continues with the presentation of power quality analyzer software design and then is completed with metrological characterization of the instrument prototype, in terms of measurement accuracy and speed of execution.

The paper analyses an effective method of increasing accuracy of active power measurement (and energy measurement) by non-coherent sampling. The measurement bias caused by non-coherent sampling are reduced by windowing the instantaneous power sequence of samples by various generalized cosine windows. Active power is found by processing signal in time domain, without using FFT. Newly obtained analytical formulae are given, a comparison to classical method and numerical simulations verifying the derived formulae are presented. A simple method of compensation multiplexing delay by measurement using multiplexing DAQ plug-in board is explained and verified both in simulation and measurement. Application of windowing for measurement of multi-frequency signals is also included, formula for standard uncertainty of active power estimate is given. Basic numerical integration methods applied to quantized input signals in power computation are briefly compared, and numerical values showing decrease in power bias for selected windows are shown.

This paper presents a new method for ultrasonic ranging. It consists on continuously transmitting a signal composed by multiple sine wave segments, each containing an integer number of periods. The frequency of each segment is different from the adjacent segments, but close to the transducer resonant frequency, to minimise the filtering effects of the system. The transmitted and received signals are cross-correlated to determine the time-of-flight (TOF). Parabolic interpolation on the cross-correlation’s magnitude is used to increase the accuracy of TOF estimation. High measurement resolutions and good noise immunity is achieved.

Replacing a lamp in an outdoor installation, like roadway lighting, requires a lot of time and money. The proper maintenance strategy of installed lighting-system components is an essential element in ensuring that systems perform as designed and consequently ensure the safety. The paper presents a method for evaluating the residual life of High Pressure Sodium road lamps and for detecting incoming fault. The proposed method is based on the frequency domain analysis of the lamp current that changes its harmonic content in consequence of the aging.