A system and method for monitoring the quality of signals transmitted to a remote service area that is located outside of the broadcast area of a main broadcast site. A by-pass capacitor in conjunction with a resonant strike circuit limits high frequency ripple applied to a lamp during continuing operation. Accordingly, a revolving structure for a glasses part where when a rotational shaft is rotated, sufficient frictional resistant force is provided and entrance of dust or the like is prevented. According to the inventive method, the image element is changed in at least one size depending on the forward travel way, on at least one operational parameter of the motor vehicle andor on at least one parameter of an object identified in the range of the travel way.