Classification of digital measuring instruments

Summary

A classification schematic of digital instruments (Fig. 2) based on the above article includes the classification of digitizers by their method of comparing the unknown and known quantities, by the method used in measuring by their equipment and their output devices, that is, their method of presenting the results.

The examination of the design principles of digital instruments only with respect to these classifications shows a considerable variety of measuring methods for which these instruments can be used. It should be noted, however, that the above classification does not include many derived types of digital circuits. However, digital instruments based on intermediate types may be of great importance. Thus, for instance, the simultaneous utilization of digitizers and analogue instruments, which is characteristic for differential methods of measuring the difference between a discrete and an unknown analogue quantity, is employed in a considerable number of instruments [5,7]. In the category of intermediate types of digital instruments should also be included partly automatic instruments which comprise contact and contactless elements, digitizers based on the simultaneous utilization of different methods of comparing the unknown and known quantities, etc.

The proposed classification of digital instruments is undoubtedly not the only possible one. However, in our opinion, it covers the basic principles for designing digital instruments and indicates certain possible tendencies in their development.