A judging and controlling part 110 comprises an operation mode judging unit 111, a pulse width selecting unit 112, and a band limiting width selecting unit 113, wherein the operation mode judging unit 111 receives a signal of a gear state from a predetermined controlling device in a vehicle, and then judges the operation mode thereof. Based on a result of the judgment at the operation mode judging unit 111, the pulse width selecting unit 112 and the band limiting width selecting unit 113 control a wide band impulse generating part 120 and a band width limiting part 150, respectively.