Abstract: A measurement instrument has a plurality of operation levels with different respective sets of operational functions associated therewith. Each operational function has at least two independently selectable characteristics related thereto. When an operation level of the instrument is selected, the instrument displays the characteristics related to each operational function associated with the selected operation level, and the operator is able to select one characteristic related to the or each operational function associated with the operation level. The characteristics related to at least one of the operational functions may each have a single value, e.g. relating to a mode of operation of the instrument. If one of the characteristics has a range of values, a value of that characteristic may be selected within the range.

Abstract: A digital signal sampling system is disclosed for reconstructing the time relationship of digital data signals sampled by two sampling clock signals with different unrelated timebases. The digital data signals sampled may be the same data signal or two different data signals sampled simultaneously in two separate sampler circuits at two different unrelated sampling clock frequencies or timebases to produce first and second sampled data signals. A timebase correlation circuit produces first and second time correlation signals in the form of binary level signals in response to the receipt by a last clock pulse detector of first and second store clock signals which are derived from first and second sampling clock signals. The time correlation signals indicate by their binary level the source of the last previous clock pulse of the first and second store clock signals which was received by the timebase correlation circuit.