JPS6420411A - Azimuth display device - Google Patents

Abstract

PURPOSE:To prevent a display from flickering without deteriorating a response speed by constituting the titled device so that even if an electric signal corresponding to the advance direction becomes unsteady frequently in the vicinity of the boundary of an azimuth display area, it is not varied until it exceeds an angle hysteresis. CONSTITUTION:In a boundary memory 7, plural boundary coordinate corresponding to each boundary of azimuth display areas P1-P8 are normalized as points on the periphery and stored. Boundary vectors to these boundary coordinates are A1-A8. By the initialization, a vector product calculating circuit 61 selects boundary coordinates (X1, Y1) and (X2, Y2) used for a first vector product calculation from the boundary memory 7, and reads in the boundary vectors A1, A2. Subsequently, this circuit reads in an advance vector Q to a digital coordinate signal (x) and (y) from an A/D converting circuit 5. Next, the vector product S1=Y2x-X2y of the counterclockwise vector A2 of the vectors A1, A2 and the advance vector Q is derived. Its absolute value is compared with a prescribed value, and the movement of an azimuth indicating area is executed.