Abstract: For quantitative potential measurement of surface-wave filters, an alternating voltage with amplitude U.sub.E.sbsb.i is connected to an input transducer of the surface-wave filter. At a local region for measurement on the filter, an alternating voltage of amplitude U.sub.P arises. For each such measuring location, the voltage U.sub.P is compared to a nominal value and if it deviates therefrom, this deviation is utilized to control an amplitude of the input voltage U.sub.E.sbsb.i so as to maintain the voltage U.sub.P substantially constant. For the various measurement locations, the changes of the input voltage U.sub.E.sbsb.i are analyzed and a local attenuation factor for each measured region in the filter may be determined. By knowing a frequency of the driving alternating voltage, conclusions can be drawn concerning specific characteristics of the filter.