Relay station in a telecommunications transmission system

Claim 1

A relay station for use in a communications transmission system, including a source of carrier and a superheterodyne receiver in which the oscillations of the received radio frequency band are converted to an intermediate frequency, said receiver connected to said source of carrier, and including a first multiplexer filter circuit connected to the output of the receiver, in which the intermediate frequency band is split into a plurality of sub-bands of separate frequencies which are disposed adjacent one another, a plurality of sub-band amplifiers, each of the intermediate frequencies sub-bands, with its own particular frequencies, being assigned to a respective sub-band amplifier, a plurality of superheterodyne transmitters requiring respective transmitter carriers and connected to the outputs of respective ones of said sub-band amplifiers, a plurality of transmitter amplifiers of the same type with respect to the individual sub-bands connected to the outputs of respective ones of said transmitters, a second multiplexer filter circuit connected to and combining the outputs of all of said transmitter amplifiers, a common carrier source comprising a stable frequency oscillator which produces the transmitter carriers at the requisite frequencies and at a low power in comparison with the total power required for the individual superheterodyne transmitters, a power divider network, and a carrier amplifier, the output of said oscillator connected to said carrier amplifier and said carrier amplifier connected to the individual superheterodyne transmitters via said power divider network, wherein said carrier amplifier is connected with the receiver carrier source and the transmitter carrier source and also amplifies the carrier for the superheterodyne receiver, and comprising a band filter divider connected to the output of said carrier amplifier, said divider operating to provide suppression of the cross-modulation products of the type 2f 2 - f 1 , where f 1 and f 2 are the frequencies of the carriers for the superheterodyne transmitters and receiver, and operating to provide suppression of the noise power of the oscillator at the signal frequencies in the received frequency range.