Presented is an uniform function scheme of the measuring process with the elemental functions
- Selection of unities of measurement
- Storage of comparison quantities and comparison values
- Comparison and control unit for comparison
- Registration of the measured values and presenting the results.
This function scheme describes both analogous as well as digital gauges and measuring devices. From it an universal block scheme is developed for all gauges and measuring devices. This functional description of measuring allows fundamental statements to measuring errors. There are two possible quantisating errors. These appear both at analog as well as digital gauges and measuring devices.

Digital Signal Processing techniques allow for significant simplification of measurement arrangements and decrease measurement time during tests of radiocommunication transmitters. The paper deals with usage of time-frequency transformations for evaluation of frequency and modulation properties of FM transmitters. The method based on Short-Time Fourier Transform (STFT) has been proposed and discussed taking into account results of simulations and experiments.

The coupled time-frequency and time–scale analysis are more and more applied in the most different fields, and they are becoming a standard component of the measurement chain. To properly design a measurement chain, the metrological characteristics of the processing has to be known as for all other components such as sensors and conditioners. On these premises a systematic investigation of the metrological properties of the processing techniques considered is carried out, by applying the analysers to a set of properly designed synthetic test signals and by evaluating the result through subjective judgement by a jury. Results of the investigation are presented, giving guidelines for application.

Due to the practical convenience of fast testing conditions and the reliability of comparative accuracy, HRC hardness tests are more often used in the industrial world than such theoretical hardness scales as HV and HB. On the other hand, the HRC scale still has an uncertainty of ± 0.4 HRC, which may result from the technical difficulty of machining crystal diamond into a precisely spherical tip of a diamond indenter and the non-elastic error from a complex indenter structure under test load. Historically, loading conditions for HRC hardness tests have not been very consistent.- Faster conditions were conveniently used in the early years, but the advent of hardness blocks encouraged a preference for stricter conditions. In recent years, however, the wider industrial application of HRC testing is again making people choose faster conditions - an international trend now followed by the ISO standards. It is natural for hardness measurements to vary when testing conditions - the tester, indenter and loading requirements - are not fixed. This problem is especially true with the HRC standard - a subject discussed in this paper.

To understand the uncertainties in the calibration of hardness test blocks by NPL, it was necessary to evaluate the main factors contributing to the uncertainty in measurements made with the NPL hardness calibration machines. These factors were identified and then, where possible, directly verified. Factors that could not be directly verified were assessed using the best available information.
The verifications covered the force required to produce hardness indents, the measurement of the size of these indents, and the characterisation of the indenters.
As a result of the initial verification, modifications were made to the depth sensor on the Rockwell hardness tester.