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Fiber optics transmission system

  • US 5,812,296 A
  • Filed: 02/11/1997
  • Issued: 09/22/1998
  • Est. Priority Date: 08/23/1995
  • Status: Expired due to Fees
First Claim
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1. A fiber optics transmission system which comprises:

  • N radio access units each of which converts an up-link radio signal from a mobile radio, received by an antenna, into an up-link optical signal by means of a semiconductor laser device, converts a down-link optical signal intensity-modulated by a down-link radio signal into a down-link radio signal by means of a photodiode and transmits it to said mobile radio through said antenna, said N being an integer equal to or greater than 2;

    up-link and down-link optical fiber lines to which said N radio access units are connected in cascade; and

    a base unit which converts a down-link radio signal received from a control station into a down-link optical signal, provides it onto said down-link optical fiber line, converts an up-link optical signal received from said up-link optical fiber line into an up-link radio signal and transmits it to said control station; and

    wherein;

    said base unit comprises a noise detector for detecting beat noise, and a noise information generating section for generating noise information representing the presence of beat noise during its detection and for sending said noise information to said N radio access unit over said down-link optical fiber line; and

    said radio access units each comprises a random signal generator for repeatedly generating a random value during the presence of said noise information, and a wavelength control circuit for controlling said semiconductor laser device to randomly select one of at least N wavelengths spaced a predetermined value or more apart in accordance with said random value.

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