A broad operational range, automatic device for the change of frequency in the horizontal deflection of multi-synchronization monitors comprises an integrated circuit (2) incorporating, a frequency meter (3) being input an analog synchronization signal (S1), a phase comparator (14) having two inputs (15,16) and in turn receiving said synchronization signal (S1) on one input (15), a voltage (Vc)-controlled oscillator (12) adapted to output a signal (S3) whose frequency is depending on said voltage (Vc) and operatively linked to an output (22) of said phase comparator (14), and a counter (9) connected with its input, on the one side, to the oscillator (12) output, and on the other side, to the meter (3) output, said counter having an output (21) connected to the other input of the phase comparator (14) also forming the integrated circuit (2) output.