Wired broadcasting systems

Claim 2

A multiprogram wired system for broadcasting a plurality of differing signals which comprises a plurality of television signal sources each providing a different program, means providing with each of said television signals synchronizing signals derived from a common synchronizing source, modulator means for modulating each of said television signals with a common high-frequency wave locked to a frequency with a fixed relationship to the frequency of the synchronizing signals, means for energizing a separate pair of conductors in a wired network of said system with each television signal and a plurality of television receivers arranged for selective connection to said pairs of conductors of the wired network to derive therefrom one of said television signals.

Claim 3

A wired broadcasting system as claimed in claim 1, wherein the common synchronizing source comprises an alternating-current signal source, and a plurality of synchronizing pulse generators, one for each of said television sources locked to the alternating-current signal from said source.

Claim 4

A wired broadcasting system as claimed in claim 1, wherein the high-frequency carrier wave for each of the plurality of television signals is derived from a common high frequency oscillator device whereby the frequencies of the carrier waves of the television signals for said programs are identical.

Claim 5

A wired broadcasting system according to claim 1 wherein at least two of the plurality of television signal sources are arranged to provide color television signals which comprise a brightness information component arranged as a modulation of the corresponding carrier wave and a color information component arranged as a modulation of a subcarrier wave associated with said corresponding carrier wave, means associated with each of said two television signal sources serving to ensure that the frequencies of the subcarrier for each of said color television signals has the same, fixed, relationship to the frequency of the synchronizing signals whereby the color information components of the color television signals have identical subcarrier frequencies which are locked to that of the common synchronizing source.

Claim 6

A wired broadcasting system as claimed in claim 1, wherein the high frequency carrier wave for each of said television signals lies in the range 4-11 MHz.

Claim 7

A wired broadcasting system as claimed in claim 1, wherein the pairs of conductors of the wired network for each television signal are arranged as separate conductor pairs contained within a common cable.

Claim 8

A wired broadcasting system as claimed in claim 6 wherein the conductor pairs are twisted with each pair having a different pitch.

Claim 9

A transmitting apparatus for a wired broadcasting system for television signals which comprises a plurality of television signal sources each relating to a different program, synchronizing signal generator means coupled with each television signal source, an alternating-current signal source, means for making available at each television signal source said alternating signal, means for controlling the frequency and phase of the synchronizing signals provided by said synchronizing signal generator means at each television signal source in dependence upon the frequency and phase of said alternating-current signal whereby the television signals produced by each of said television signal sources are generated in unison, means for receiving at a wired broadcasting substation at least some of said plurality of television signals, means for translating the received signals to a common carrier wave frequency and means for applying said frequency translated television signals to different conductor pairs of a wired broadcasting cable network.

Claim 10

A transmitting apparatus for a wired broadcasting system for television signals which comprises a plurality of television signal sources each relating to a different program, synchronizing signal generator means coupled with each television signal source, an alternating-current signal source, means for making available at each television signal source said alternating signal, means for controlling the frequency and phase of the synchronizing signals provided by said synchronizing signal generator means at each television signal source in dependence upon the frequency and phase of said alternating-current signal whereby the television signals produced by each of said television signal sources are generated in unison, means for receiving at a wired broadcasting substation at least some of said plurality of television signals, means for translating the received signals to a common carrier wave frequency and means for applying said frequency translated television signals to different conductor pairs of a wired broadcasting cable network.

Claim 11

A transmitting apparatus as claimed in claim 8, wherein at least two of said television signal sources are arranged to provide color television signals wherein the color information component Is transmitted as a modulation of a subcarrier wave and wherein means are provided for determining that the frequency of said subcarrier wave bears a fixed relationship to the frequency of the synchronizing signals provided by the synchronizing signal generator means at said television signal source, said color information subcarrier waves of the two color television signals thereby having identical frequencies.

Claim 12

A transmitting apparatus as claimed in claim 8, wherein the frequency of the carrier waves applied to the conductor pairs of said cable network is controlled in accordance with the frequency of a common oscillator device.

Claim 13

A transmitting apparatus as claimed in claim 10, wherein said common oscillator device is arranged to provide oscillations at a frequency determined by that of the alternating-current signal.

Claim 14

A transmitting apparatus as claimed in claim 10, wherein the frequency of said carrier waves lies in the range 4-11 MHz.

Claim 15

A transmitting apparatus as claimed in claim 8, wherein at least some of said television signal sources are arranged to provide television signals comprising a modulation component of a carrier wave, said carrier wave being provided by a carrier wave generating means having associated therewith frequency control means responsive to the frequency of said alternating-current signal whereby said carrier waves have frequencies which bear a fixed relationship to that of said alternating-current signal.

Claim 16

A transmitting apparatus as claimed in claim 13, wherein said source of alternating-current signal is provided by a frequency standard transmission.