Optical space transmission communicating device

Abstract

Abstract PURPOSE:To reduce energy consumption without degrading a reception condition by providing a bit error detecting means, which detects the bit error rate of a received digital signal, and a transmission intensity control means in a portable unit. CONSTITUTION:An optical signal from a base unit is photo-detected by a photo- diode 25 of a receiver RP1 in a portable unit PU1, passed through an amplifier 26, etc., demodulated by a demodulator 29 and after that, returned to the original digital signal by a code reverse converting device 30. In such a case, processing to detect and correct a bit error is executed in the device 30 and the data of the bit error rate are sent to a control circuit 31. In the circuit 31, an LED driver 23 is controlled so that the light emission intensity of an LED24 can be small when the bit error rate to be detected by the device 30 is small (when a transmission condition is satisfactory) and the light emission intensity of the LED24 can be large when the bit error rate is large. Thus, when the transmission condition is satisfactory, for example, when a distance between the units is short, etc., transmitting force is limited and the energy consumption can be reduced without degrating the reception condition.

Inventors

• 👤 Masahiro Okamura
• 👤 雅裕 岡村
• 👤 Toshimasa Hamada
• 👤 敏正 浜田
• 👤 Norio Yoshida
• 👤 吉田　式雄

Bibliographic Details