The present invention relates to methods for enhancing gastrointestinal motility. In the power source voltage generating circuit, output stage transistors are driven by comparing a plurality of reference voltages produced by a plurality of resistors connected in series to one another with output voltages of a plurality of differential amplifiers connected in parallel to one another and varying gate voltages. When tip squealer 37 is formed, hole 38 is formed so that its opening portion is provided at the side surface of tip squealer 37. The first auxiliary electrode is disposed at the portion of the first side located at a side of the second area. The data processor can be designed to include a correlator, a symbol demodulation and combiner, a first accumulator, and a second buffer, or a combination thereof.