Optimization of single phase unidirectional transducers (SPUDT) is main problem in the design of low-loss SAW filters. Here we deal with distributed acoustic reflection transducers, each elementary cell (one wavelength) of that includes not more than one "hot" electrode and/or one, two, three or four grounded electrodes. For assembling the input and output SPUDTs we use more than ten different cell types that are considered as elementary SAW sources and SAW reflectors with different magnitudes and phases, depending on widths and positions of electrodes.