training in the provisions of measure numbers often reported

摘要

For the measurement of the unknown frequency or period of a measuring signal within a given measuring time interval the number of full cycles of the measuring signal within the measuring time interval are counted in a first group of counting circuits and the fractions of the measuring signal cycles at the beginning and at the end of the measuring time interval are counted with the aid of a clock pulse train of fixed frequency in a second group of counting circuits. For a measuring signal of high frequency, the capacity of the first group should be large, whereas that of the second group need only be small, because the fractions at the beginning and at the end of the measuring time interval are correspondingly small. For a measuring signal of low frequency this is just the other way round, so that the total number of counting circuits is independent of the frequency and is only determined by the required resolution. When these counting circuits are divided into groups in accordance with the frequency of the measuring signal, the required number of counting circuits can be substantially reduced. In order to ensure that the values for determining the unknown frequency are obtained within the measuring time interval only, the counting circuits may be divided into three groups, so that the subsequent computing equipment may also be reduced considerably.