A digital clock generator includes a base clock generator for generating a base clock signal at a variable base clock frequency in response to a control signal. The system includes an electronic signal converter, a scanner, a windshield video camera, cockpit video camera, and smoke over-goggles equipped with two eye level electronic video display devices. The invention aims at and succeeds in providing peroxygenated bleaching agents more stable and more efficient than those known in prior art. Indication is made as to whether the service level parameter values satisfy the predetermined service thresholds.