Modem to be coupled to a directional transmission line of an SS multiplex communication network

In a transmitter-receiver for use in a spread spectrum multiplex communication network comprising an up and a down transmission line and a plurality of modems coupled to said up and said down transmission lines, said transmitter-receiver being comprised by each of said modems to be responsive to a first spread spectrum signal received from said down transmission line and comprising a spread spectrum signal into which a first of a plurality of different pseudo noise code sequences is modulated by a particular information signal for reproducing said particular information signal and to be responsive to a transmission information signal for supplying towards a preselected one of said modems through said up transmission line a second spread spectrum signal comprising a spread spectrum signal into which a second of said pseudo noise code sequences is modulated by said transmission information signal, said transmitter-receiver including reception spread spectrum signal producing means responsive to said first spread spectrum signal for producing a reception spread spectrum signal, pseudo noise code sequence generating means for generating at least one of said different pseudo noise code sequences as said first and said second pseudo noise code sequences, first multiplying means for multiplying said reception spread spectrum signal by the first pseudo noise code sequence generated by said pseudo noise code sequence generating means to produce a first multiplied signal, low frequency component extracting means for extracting a low frequency component from said first multiplied signal to produce a low frequency signal, means responsive to said low frequency signal for producing said particular information signal, second multiplying means for multiplying said transmission information signal by the second pseudo noise code sequence generated by said pseudo noise code sequence generating means to produce a second multiplied signal, and second spread spectrum signal supplying means for supplying said second multiplied signal as said second spread spectrum signal to said up transmission line, said different pseudo noise code sequences being generated by clocks having a predetermined clock period in compliance with a single generating polynomial and with different initial values, respectively, said predetermined clock period defining a predetermined frequency band, the improvement wherein:

• said predetermined frequency band is made to comprise first through I-th partial frequency bands having a substantially common partial bandwidth and not substantially overlapping each other, where I represents a predetermined integer greater than unity;
• said modems being classified into first through I-th groups, each group consisting of at least two of said modems, said first through said I-th partial frequency bands being allotted to said first through said I-th groups, respectively, different ones of said different pseudo noise code sequences being assigned to the respective modems in each group, said each modem being a modem in a group allotted with a particular one of said partial frequency bands, said preselected modem being a modem in a group allotted with a preselected one of said partial frequency bands, said first spread spectrum signal comprising a particular spread spectrum component in said particular partial frequency band;
• said reception spread spectrum signal producing means comprising means for extracting said particular spread spectrum component from said first spread spectrum signal as said reception spread spectrum signal;
• said second spread spectrum signal supplying means comprising:
• first through I-th filters having passbands at said first through said I-th partial frequency bands, respectively;
• and
• means for selecting one of said first through said I-th filters that has a passband at said preselected partial frequency band, said selected filter being responsive to said second multiplied signal for producing said second spread spectrum signal in said preselected partial frequency band.

In a transmitter-receiver for use in a spread spectrum multiplex communication network comprising an up and a down transmission line and a plurality of modems coupled to said up and said down transmission lines and dealing with information signals of a plurality of different data clock periods, said transmitter-receiver being comprised by a modem dealing with information signals of one of said different data clock periods to be responsive to a first spread spectrum signal received from said down transmission line and comprising a spread spectrum signal into which a first of different pseudo noise code sequences is modulated by a particular information signal having said one data clock period for reproducing said particular information signal and to be responsive to a transmission information signal having said one data clock period for supplying towards a preselected one of the modems dealing with information signals of said one data clock period through said up transmission line a second spread spectrum signal comprising a spread spectrum signal into which a second of said pseudo noise code sequences is modulated by said transmission information signal, said transmitter-receiver including reception spread spectrum signal producing means responsive to said first spread spectrum signal for producing a reception spread spectrum signal, pseudo noise code sequence generating means for generating at least one of said different pseudo noise code sequences as said first and said second pseudo noise code sequences, first multiplying means for multiplying said reception spread spectrum signal by the first pseudo noise code sequence generated by said pseudo noise code sequence generating means to produce a first multiplied signal, low frequency component extracting means for extracting a low frequency component from said first multiplied signal to produce a low frequency signal, means responsive to said low frequency signal for producing said particular information signal, second multiplying means for multiplying said transmission information signal by the second pseudo noise code sequence generated by said pseudo noise code sequence generating means to produce a second multiplied signal, and second spread spectrum signal supplying means for supplying said second multiplied signal as said second spread spectrum signal, the improvement wherein:

• said different pseudo noise code sequences consist of pseudo noise code sequences of a first through a Q-th family, where Q represents a predetermined integer greater than unity, said first-family pseudo noise code sequences being for at least one modem dealing with information signals of a shortest of said different data clock periods, said Q-th-family pseudo noise code sequences being for at least one modem dealing with information signals of a longest of said different data clock rates, said first-family through said Q-th-family pseudo noise code sequences being given by pseudo noise code sequences of a first through a Q-th kind, said first-kind pseudo noise code sequences being generated by clocks having a first clock period in compliance with a first generating polynomial specifying a first frame period not longer than said shortest data clock period and with different initial values, respectively, the q-th-kind pseudo noise code sequences being generated by clocks having a q-th clock period in compliance with a q-th generating polynomial specifying a q-th frame period and with different initial values, respectively, where q represents an integer between two and Q, both inclusive, said q-th clock period being equal to an integral multiple of the (q- 1)-th frame period, said integral multiple being selected from natural numbers for each of the second through the Q-th clock periods, the Q-th frame period being not longer than said longest data clock period, said first-family pseudo noise code sequences being given by those of said first-kind pseudo noise code sequences, respectively, which are preselected with at least one first-kind pseudo noise code sequence left remaining, each of the q-th-family pseudo noise code sequences being given by a product of a first through a q-th component pseudo noise code sequences, the first through the (q-1)-th component pseudo noise code sequences being those preselected one from the at least one remaining pseudo noise code sequence of each of the first through the (q-1)-th kinds, the q-th component pseudo noise code sequence being one preselected from the q-th-kind pseudo noise code sequences with at least one q-th-kind pseudo noise code sequence left remaining unless q is equal to Q, each of said first through said q-th component pseudo noise code sequences used to provide said product being preselected so as not to be in duplication with any one of the first through the q-th component pseudo noise code sequences used to provide the products for others of said q-th-family pseudo noise code sequences;
• said pseudo noise code sequence generating means being for generating at least one q'-th-family pseudo noise code sequence as said first and said second pseudo noise code sequences, where q' represents an integer selected between unity and Q, both inclusive, so that the q'-th frame period be not longer than said one data clock period and be nearest thereto among said first through said Q-th frame periods.

In a transmitter-receiver for use in a spread spectrum multiplex communication network comprising an up and a down transmission line and a plurality of modems coupled to said up and said down transmission lines and dealing with information signals of a plurality of different data clock periods, said transmitter-receiver being comprised by a modem dealing with information signals of one of said different data clock periods to be responsive to a first spread spectrum signal received from said down transmisson line and comprising a spread spectrum signal into which a first of different pseudo noise code sequences is modulated by a particular information signal having said one data clock period for reproducing said particular information signal and to be responsive to a transmissfon information signal having said one data clock period for supplying towards a preselected one of the modems dealing with information signals of said one data clock period through said up transmission line a second spread spectrum signal comprising a spread spectrum signal into which a second of said pseudo noise code sequences is modulated by said transmission information signal, said transmitter-receiver including reception spread spectrum signal producing means responsive to said first spread spectrum signal for producing a reception spread spectrum signal, pseudo noise code sequence generating means for generating at least one of said different pseudo noise code sequences as said first and said second pseudo noise code sequences, first multiplying means for multiplying said reception spread spectrum signal by the first pseudo noise code sequence generated by said pseudo noise code sequence generating means to produce a first multiplied signal, low frequency component extracting means for extracting a low frequency component from said first multiplied signal to produce a low frequency signal, means responsive to said low frequency signal for producing said particular information signal, second multiplying means for multiplying said transmission information signal by the second pseudo noise code sequence generated by said pseudo noise code sequence generating means to produce a second multiplied signal, and second spread spectrum signal supplying means for supplying said second multiplied signal as said second spread spectrum signal, the improvement wherein:

• said different pseudo noise code sequences consist of pseudo noise code sequences of a first through a Q-th family, where Q represents a predetermined integer greater than unity, said first-family pseudo noise code sequences being for at least one modem dealing with information signals of a shortest of said different data clock periods, said Q-th-family pseudo noise code sequences being for at least one modem dealing with information signals of a longest of said different data clock periods, said first-family through said Q-th-family pseudo noise code sequences being given by pseudo noise code sequences of a first through a Q-th kind said first-kind pseudo noise code sequences being generated by clocks having a first clock period in compliance with a first generating polynomial specifying a first frame period not longer than said shortest data clock period and with different initial values, respectively, the q-th-kind pseudo noise code sequences being generated by clocks having a q-th clock period in compliance with a q-th generating polynomial specifying a q-th frame period and with different initial values, respectively, where q represents an integer between two and Q, both inclusive, said q-th clock period being equal to an integral multiple of the (q-1)-th frame period, said integral multiple being selected from natural numbers for each of the second through the Q-th clock periods, the Q-th frame period being not longer than said longest data clock period, said first-family pseudo noise code sequences being given by combinations of a first set, respectively, each first-set combination consisting of only one pseudo noise code sequence preselected from said first-kind pseudo noise code sequences with at least one first-kind pseudo noise code sequence left remaining, each of the q-th-family pseudo noise code sequences being given by a product of a first through a q-th component pseudo noise code sequences, the first through the (q-1)-th component pseudo noise code sequences being those preselected one from the at least one remaining pseudo noise code sequence of each of the first through the (q-1)-th kinds, the q-th component pseudo noise code sequence being one preselected from the q-th-kind pseudo noise code sequences with at least one q-th-kind pseudo noise code sequence left remaining unless q is equal to Q, each of said first through said q-th component pseudo noise code sequences used to provide said product being preselected so as not to be in duplication with any one of the first through the q-th component pseudo noise code sequences which are used to provide the products for others of said q-th-family pseudo noise code sequences;
• said pseudo noise code sequences generating means being for generating at least one component pseudo noise code sequence of the q'-th-set combination for use as said first and said second pseudo noise code sequences, where q' represents an integer selected between unity and Q, both inclusive, so that the q'-th frame period be not longer than said one data clock period and be nearest thereto among said first through said Q-th frame periods;
• said first multiplying means comprising means for producing said first multiplied signal by multiplying said reception spread spectrum signal in a predetermined order by the at least one component pseudo noise code sequence of said q'-th-set combination for use as said first pseudo noise code sequence;
• said second multiplying means comprising means for producing said second multiplied signal by multiplying the transmission information signal supplied thereto in a preselected order by at least one component pseudo noise code sequence of said q'-th-set combination for use as said second pseudo noise code sequence.