PURPOSE: To obtain a base band communications system with less transmission error and immune to noises by utilizing the data coding system in which a signal spectrum component is in existence at the outside of a low frequency noise spectrum region.
CONSTITUTION: Communication data T are converted into a code not including a low frequency component in its power spectrum at a code conversion section 3. The data subjected to code conversion are converted into an infrared ray communication beam TD at a light emitting section 1 via an SP conversion section 4 and a pulse drive section 2 and sent to a transmission line toward an on-vehicle equipment. Reception beam RB received by the on-vehicle equipment includes noise N such as the sun ray and the beam is converted into an electric signal at a light receiving section 6 and passes through an HPF 7. In this case, since the separated from each other, the HPF 7 eliminates only the low frequency noise spectrum.
UEDA FUKUMI
MANABE FUMIO
OKADA ISHIYA
| JPH0431215A | 1992-02-03 | |||
| JPS61290827A | 1986-12-20 | |||
| JPS594251A | 1984-01-11 |