Abstract: Logic level shifting circuits are described in which integrated circuits process binary logic input signals of logic levels different from the input logic levels of said integrated circuits but within the ranges of tolerance and safety of said integrated circuits. Such logic level shifting techniques are used as a simple but effective method to cut down power consumption in luminous displays using seven-segment LED's or the like which may be placed in series as a result of logic level shifting between the respective counters and decoders which control them.

Abstract: A programmable number of pulses N, of one or more auxiliary frequencies fa, is inserted between pulses of the frequency f.sub.1 to be processed. The resulting frequency N.f.sub.1, where N is a positive number (N can be fractional), is at any moment proportional to input frequency f.sub.1 where N, the proportionality factor, varies at will and can assume any positive number value. Pulse insertion results in a frequency shift of positive or negative value and succeeds continuously and without any information loss i.e. the pulse train has not to be interrupted and is processed "on (the) line". The same method described used for higher frequencies eliminates the known .+-.1 count problem as it can register fractions of a pulse.