Signal separation apparatus

A signal separation apparatus comprising:

• a piezoelectric substrate;
• a reception filter located on the piezoelectric substrate;
• and
• a transmission filter located on the piezoelectric substrate;
• wherein
• the reception filter includes an input terminal, an output terminal, and first, second and third longitudinally coupled resonator elastic wave filter devices electrically connected in series or in parallel with one another on at least one of an input terminal side and an output terminal side;
• the first, second and third longitudinally coupled resonator elastic wave filter devices are configured such that first, second and third group-A longitudinally coupled resonator elastic wave filter units are respectively cascade-connected with first, second and third group-B longitudinally coupled resonator elastic wave filter units in two stages, and the longitudinally coupled resonator elastic wave filter units each include an IDT electrode;
• a virtual ground wiring line that is not connected to a ground potential and that connects ground terminals of adjacent ones of the longitudinally coupled resonator elastic wave filter units to each other, on at least one of a first, second, and third group-A longitudinally coupled resonator elastic wave filter units side and a first, second, and third group-B longitudinally coupled resonator elastic wave filter units side, is further provided;
• and
• the transmission filter is located in a region extending from the reception filter in an interstage direction of the two-stage cascade connection in the reception filter.