Abstract: A method derives a frequency of a pulse signal from a line frequency. The method includes measuring a period of a line frequency pulse signal having the line frequency using a measured frequency derived from an oscillator frequency. The method further includes determining if the period of the line frequency pulse signal is within a predetermined tolerance limit. The line frequency is used to derive the frequency of the pulse signal when the period is determined to be within the predetermined tolerance limit, and the oscillator frequency is used to derive the frequency of the pulse signal when the period is determined to be outside the predetermined tolerance limit.

Abstract: In order to obtain a simple construction of an electricity meter (1), the invention provides that the meter comprises a highly integrated input module (3a, 3b, 3c) in which an analog-digital converter (5a, 5b) and an output module (7a) are integrated. A multiplying means (21) can optionally be integrated. Such an input module (3a, 3b, 3c), in combination with conventional components, especially microprocessors, makes it possible to produce an electricity meter which comprises a simple construction and which is of a single-phase and multi-phase type (also for a plurality of consumers).