| 摘要 |
PURPOSE:To make an updating direction clear and to obtain the display device only by adding a simple circuit by changing ground colors at every period of a transmission and reception part. CONSTITUTION:A detection signal obtained from the transmission and reception part 1 is stored in a RAM5 through a ground color switching circuit composed of an A/D converting circuit. A signal read out of the RAM5 is converted into a color signal with a predetermined level, and each color signal is transmitted to a signal converting part 6 for digital-analog conversion. The signal from the transmission and reception part 1, on the other hand, is guided to the RAM5 through a direction counter 8 which counts a rotation pulse of, for example, every 1 deg. according to a reference direction. Then, an FF14 which divides a bow pulse into two leads a high-level and a low-level signal to the ground color switching circuit 4. Then, the ground color of a signal with no signal level among signals written in the RAM is changed between, for example, dark blue and light blue very time the transmission and reception part faces the bow. |
