초록 ▼

A plurality of information processors are coupled by respective modems to a communication medium at points thereof. Transmission and reception of information signals among the modems are effected through a headed located at a predetermined point on the communication medium. A pilot signal generator

A plurality of information processors are coupled by respective modems to a communication medium at points thereof. Transmission and reception of information signals among the modems are effected through a headed located at a predetermined point on the communication medium. A pilot signal generator is provided which sends out a pilot signal having a predetermined reference level through the headend to the communication medium. Each modem is arranged to properly adjust the gain of its transmitting amplifier according to a reception level of the pilot signal for an improvement of signal transmission quality and a reliable detection of a signal collision.

대표청구항 ▼

An information transmission system comprising: a communication line having a transmission path and a reception path and means for coupling information signals present on said transmission path to said reception path at a predetermined point of said line; a plurality of information processing devices

An information transmission system comprising: a communication line having a transmission path and a reception path and means for coupling information signals present on said transmission path to said reception path at a predetermined point of said line; a plurality of information processing devices; a plurality of modems for coupling said information processing devices to said communication line at arbitrary points thereof and for permitting transmission and reception of information signals among said information processing devices through said communication line, each modem including a transmitting amplifier to transmit an information signal from a corresponding information processing device to said transmission path of said communication line and a receiving amplifier to receive an information signal transmitted to said transmission path by any of said modems through said predetermined coupling point of said transmission and reception paths and said reception path; a pilot signal providing means for sending out to said communication line a pilot signal of a predetermined reference level which is capable of being received by said receiving amplifier of each of said modems; and each of said modems further including: reception level detecting means coupled to said receiving amplifier for detecting the reception level of a signal received through said reception path; and gain adjusting means responsive to said reception level detecting means for adjusting the gain of said transmitting amplifier such that the reception level of a transmission signal, which is transmitted to said transmission path by said transmitting amplifier and received by said receiving amplifier through said predetermined coupling point of said transmission and reception paths and through said reception path, becomes substantially equal to the reception level of the pilot signal received by said receiving amplifler.