| 摘要 |
The invention relates to a cordless communication system for the transmission of information between at least two units (1, 2), of which one unit (1) is equipped with one or more light-emitting diodes (3), preferably diodes adapted to generate infrared light (IR-light), and the other unit (2) is equipped with one or more photodetectors (5), preferably adapted to receive IR-light. One of the units also includes means for modulating the light generated by the light-emitting diodes in dependence on the desired information content, and the other unit is provided with means for interpreting the received modulated light signal in order to obtain the prevailing information content. The means of one unit (1) is intended to form, via respective diodes (3), a light change which corresponds to a continuous function. The modulation for information transmission conforms to the principles of frequency modulation and/or amplitude modulation, and the means of the other unit (2) evaluates the prevailing light change and/or frequency change. Each unit (1) includes a switch device (8c) which is able to alternate frequencies, one frequency being intended for internal communication (1, 2) and one intended for external communication (1, 1' and 1, 2' respectively). |
