Abstract: A quarter-wave distributed-constant dielectric filter or resonator having a ceramic body which typically is composed principally of barium titanate. The ceramic filter body has one or more resonance holes extending therethrough. A conductive covering of silver or the like on the filter body has a portion formed on the surface defining each resonance hole. Mounted in each resonance hole is a prefabricated capacitor having a first terminal extending from within the resonance hole. The second terminal is electrically coupled to the conductive covering on the surface of the resonance hole. The capacitance of the capacitor or capacitors can be known before they are mounted to the filter body, so that the filter is readily manufacturable to exact electrical characteristics desired.

Abstract: A signal generator which generates one pulse for each predetermined distance of travel of a vehicle. A rotary member is driven by the rotation of a wheel of the vehicle, and the rotary member has arranged thereon reflecting and non-reflecting portions alternately with each other about a rotary shaft of the rotary member. A pair of optical transmission lines are disposed to confront at one end the surface of the rotary member on which the reflecting and non-reflecting portions are arranged. Light is emitted from a light emitting element to the other end of one of the optical transmission line, and light reflected by the rotary member is incident to the other optical transmission line and received by a photo detector provided at the other end of the optical transmission line. In dependence on whether the reflecting or non-reflecting portion of the rotary member lies opposite to the optical transmission lines, the output from the photo detector varies to provide a travel-distance signal.