inductive or capacitive sensors these gives a coarse indication of weight and therefore determines which u201c zone u201d the saw sensor was operating in according to the present invention two weight sensors are provided each oscillating at a different frequency although both sensors will be displaced by more than one wavelength they will differ in wavelength fig9 illustrates the frequency change of two weight sensors operating at different frequencies of oscillation one shown in a solid line and the other shown in a dashed line those skilled in the art will appreciate that at any given weight the pair of frequency values will be unique as described above and in the previously incorporated patents a differential pair of saw weight sensors may be used to improve resolution when weight increases on the scale platform one sensor will have an increased distance between the transmitter and receiver and the other will have a decreased distance this is best shown in fig9 11 of previously incorporated u s pat no 5 910 647 according to the present invention this arrangement can also be used to locate the zone of oscillation by using different frequencies for each sensor a new method according to the invention is to use different frequencies for each of two or more saw weight sensors in a differential format fig1 illustrates the change in frequency of two differential oscillators operating at different frequencies there have been described and illustrated herein several embodiments of an electronic weighing apparatus utilizing surface acoustic waves while particular embodiments of the invention have been described it is not intended that the invention be limited thereto as it.