Use of equalizers in satellite communication transmission systems

Claim 2

A satellite communications transmission system having at least one satellite transponder and at least two ground radio stations between which multi-channel signals is to be transmitted at radio frequency via said transponder, said transponder having a distortion characteristic which is generally U-shaped as a function of frequency, a transmitter at one of said ground statons, a single distortion remover for compensating the entire radio frequency in said transmitter, said transmitter having a plurality of individual signals channels, means in each of said channels for converting the signal in each channel to an intermediate frequency, means combining said converted signals to a common intermediate frequency band, said distortion remover receiving the output of said combined converted common intermediate frequency band and predistorting it with a characteristic having an inverted U-shape which is opposite to the distortion characteristic of said transponder, means for converting the output of said distortion remover to a radio frequency signal and radiating it to said transponder, and means at said other ground station for receiving said radio frequency signal from said transponder and demodulating the individual signals from said radio frequency signal.

Claim 3

A satellite communications transmission system having at least one satellite transponder and at least two ground radio stations between which multi-channel signals is to be transmitted at radio frequency via said transponder, said transponder having a distortion characteristic which is generally U-shaped as a function of frequency, a transmitter at one of said ground stations, said transmitter having a pluraity of individual signal channels, a plurality of frequency converters each receiving individual signals of said plurality of individual signal channels and converting each of them to intermediate frequencies, a plurality of distortion removers each having the same frequency characteristics which is inverted U-shape and opposite to the distortion characteristic of said transponder and each receiving individual signals after they have been converted to intermediate frequencies and predistorting them, means connected to the distortion remover in each channel for converting said intermediate frequencies to a radio frequency, means for combining said converted radio frequencies to a common radio frequency band and radiating it to said transponder, and means at said other ground station for receiving said radio frequency band from said transponder and demodulating the individual signals from said radio frequency band signal.

Claim 4

A satellite communications transmission system having at least one satellite transponder and at least two ground radio stations between which multi-channel signals is to be transmitted at radio frequency via said transponder, said transponder having a distortion characteristic which is generally U-shaped as a function of frequency, a transmitter at one of said ground stations, said transmitter having a pluraity of individual signal channels, a plurality of frequency converters each receiving individual signals of said plurality of individual signal channels and converting each of them to intermediate frequencies, a plurality of distortion removers each having the same frequency characteristics which is inverted U-shape and opposite to the distortion characteristic of said transponder and each receiving individual signals after they have been converted to intermediate frequencies and predistorting them, means connected to the distortion remover in each channel for converting said intermediate frequencies to a radio frequency, means for combining said converted radio frequencies to a common radio frequency band and radiating it to said transponder, and means at said other ground station for receiving said radio frequency band from said transponder and demodulating the individual signals from said radio frequency band signal.