Abstract: A radar apparatus includes an antenna section that transmits and receives a radar wave, a high-frequency circuit section that handles a high-frequency signal, and a low-frequency circuit section that handles a low-frequency signal. The low-frequency circuit section is arranged on a major face of a main printed board. The high-frequency circuit section and the antenna section are arranged respectively on first and second faces of a secondary printed board. Moreover, the secondary printed board is mounted to a space on the major face of the main printed board which is not occupied by the low-frequency circuit section. Consequently, it becomes possible to use the high-frequency signal by using an insulating material, which is necessary for suppression of dielectric loss, only for the secondary printed board.

Abstract: A radar apparatus includes an antenna section that transmits and receives a radar wave, a high-frequency circuit section that handles a high-frequency signal, and a low-frequency circuit section that handles a low-frequency signal. The low-frequency circuit section is arranged on a major face of a main printed board. The high-frequency circuit section and the antenna section are arranged respectively on first and second faces of a secondary printed board. Moreover, the secondary printed board is mounted to a space on the major face of the main printed board which is not occupied by the low-frequency circuit section. Consequently, it becomes possible to use the high-frequency signal by using an insulating material, which is necessary for suppression of dielectric loss, only for the secondary printed board.

Abstract: An A/D converter performs successive A/D conversion operations that are synchronized with respective periods of an externally supplied clock signal. A set of output digital data produced from the A/D converter, following each A/D conversion, is acquired a plurality of times in succession within an interval that extends to the start of the next A/D conversion operation. If identical sets of data are not obtained in the successive acquisitions, then it is determined that there is failure of the A/D converter due to loss of the external clock signal.

Abstract: An A/D converter performs successive A/D conversion operations that are synchronized with respective periods of an externally supplied clock signal. A set of output digital data produced from the A/D converter, following each A/D conversion, is acquired a plurality of times in succession within an interval that extends to the start of the next A/D conversion operation. If identical sets of data are not obtained in the successive acquisitions, then it is determined that there is failure of the A/D converter due to loss of the external clock signal.