Communication system

Claim 2

A communication system (10,310) comprising: a head end device (14,314) for receiving and translating bursts of information received in a partial response format to continuous information in a partial response format and for transmitting the continuous information; a first broadband communications medium (12U,312U) coupled to the head end device; a second broadband communications medium (12D,312D) coupled to the head end device (14,314); and a plurality of node devices (16,18,316,318) each having modulator means (64,364) coupled to the first broadband communications medium (12U,312U) for transmitting signals upstream via the head end device (14,314) and having demodulator means (72,372) coupled to the second broadband communications medium (12D,312D) for receiving signals downstream from the head end device (14,314), each modulator means (72,372) comprising means for communicating bursts of information in a partial response format with zero energy output for a zero value input, and each demodulator means (72,372) comprising means for receiving continuous information in a partial response AM-PSK format.

Claim 3

A communication system (310) comprising: a head end device (314) for receiving and translating bursts of information received in a partial response format to continuous information in a partial response format and for transmitting the continuous information; a first broadband communications medium (312U) coupled to the head end device (314); a second broadband communications medium (312D) coupled to the head end device (314); and a plurality of node devices (316,318) each having modulator means (364) coupled to the first broadband communications medium (312U) for transmitting signals upstream via the head end device (314) and having demodulator means (372) coupled to the second broadband communications medium (312D) for receiving signals downstream from the head end device (314), each modulator means comprising means (376) for communicating bursts of information in an offset quadrature phase shift keyed (OPSK) format, and each demodulator means (372) comprising means (376) for receiving continuous information in the OPSK format.

Claim 4

A communication system (310) comprising: a head end device (314) for receiving and translating bursts of information received in a partial response format to continuous information in a partial response format and for transmitting the continuous information; a first broadband communications medium (312U) coupled to the head end device (314); a second broadband communications medium (312D) coupled to the head end device (314); and a plurality of node devices (316,318) each having modulator means (364) coupled to the first broadband communications medium (312U) for transmitting signals upstream via the head end device (314) and having demodulator means (372) coupled to the second broadband communications medium (312D) for receiving signals downstream from the head end device (314), each modulator means comprising means (376) for communicating bursts of information in an offset quadrature phase shift keyed (OPSK) format, and each demodulator means (372) comprising means (376) for receiving continuous information in the OPSK format.

Claim 5

A communication system as claimed in claim 1 or 2 wherein the modulator means (68,368) comprises means for transmitting the bursts of information with an efficiency of one bit per Hertz.

Claim 6

A communication system as claimed in claim 1, 2 or 3 wherein the head end device (14,314) comprises means for transmitting (40,340) the continuous information with an efficiency of one bit per Hertz.

Claim 7

A communication system as claimed in claim 1, 2, 3 or 4 wherein the first broadband communication medium (12U, 312U) and the second broadband communication medium (12D,313D) are separate frequency channels on a single physical medium (12,312) and the head end device (14,314) includes a frequency translating means (58,358).

Claim 8

A communication system (10) for transmitting information from a source node (16) to a target node (18) comprising: a head end device (14); a unidirectional transmitting medium (12U) coupling each node (16) in a source path to and terminating at the head end device (14); a unidirectional receiving medium (12D) originating from the head end device (14) and coupling to each target node (18); means (64) at the source node (16) for transmitting the information as a class four, three-level partial response signal on a three-­frequency shift keyed (FSK) carrier on the transmitting medium (12U) from the node (16); the head end device (14) comprising: a) head end receiving means (36) for receiving the class four partial response signal, with a frequency modulation (FM) receiver (36) to obtain a received signal, the head end receiving means (36) including: 1) a limiter circuit means (46) for hard limiting the received signal to obtain a limited signal within a dynamic range suitable for discrimination; and 2) a discriminator circuit means (48) for discriminating the limited signal to extract a bit pattern of the information: b) head end translating means (52) for transferring signals received at the head end device (14) of the transmitting medium (12U) to the receiving medium (12D); c) means (40) for transmitting continuously a class one, three-level partial responses signal on a continuous carrier on the receiving medium (12D) from head end device (14); and d) means (32) for modulating the continuous carrier with the bit pattern of the information when the bit pattern of the information is present and modulating the continuous carrier with a repetitive bit pattern when the bit pattern of the information is not present; and target node receiving means (72) for receiving the continuous carrier at the target node (18) on the receiving medium (12D), the target node receiving means (72) including: a) envelope detector means (74) for detecting the modulated continuous carrier; and b) analog to digital converting means (76) for extracting the bit pattern of said information from said carrier by strobing the bit pattern in synchronism with a system clock.

Claim 9

A communication system (10) for transmitting information from a source node (16) to a target node (18) comprising: a head end device (14); a unidirectional transmitting medium (12U) coupling each node (16) in a source path to and terminating at the head end device (14); a unidirectional receiving medium (12D) originating from the head end device (14) and coupling to each target node (18); means (64) at the source node (16) for transmitting the information as a class four, three-level partial response signal on a three-­frequency shift keyed (FSK) carrier on the transmitting medium (12U) from the node (16); the head end device (14) comprising: a) head end receiving means (36) for receiving the class four partial response signal, with a frequency modulation (FM) receiver (36) to obtain a received signal, the head end receiving means (36) including: 1) a limiter circuit means (46) for hard limiting the received signal to obtain a limited signal within a dynamic range suitable for discrimination; and 2) a discriminator circuit means (48) for discriminating the limited signal to extract a bit pattern of the information: b) head end translating means (52) for transferring signals received at the head end device (14) of the transmitting medium (12U) to the receiving medium (12D); c) means (40) for transmitting continuously a class one, three-level partial responses signal on a continuous carrier on the receiving medium (12D) from head end device (14); and d) means (32) for modulating the continuous carrier with the bit pattern of the information when the bit pattern of the information is present and modulating the continuous carrier with a repetitive bit pattern when the bit pattern of the information is not present; and target node receiving means (72) for receiving the continuous carrier at the target node (18) on the receiving medium (12D), the target node receiving means (72) including: a) envelope detector means (74) for detecting the modulated continuous carrier; and b) analog to digital converting means (76) for extracting the bit pattern of said information from said carrier by strobing the bit pattern in synchronism with a system clock.

Claim 10

A communication system (310) for transmitting information from a source node (316) to a target node (318) comprising: a head end device (314); a unidirectional transmitting medium (312U) coupling each node (316) in a source path to and terminating at the head end device (314); a unidirectional receiving medium (312D) originating from the head end device (314) and coupling to each target node (318); means (364) at the source node (316) for transmitting the information as an offset quadrature phase shift keyed (OQPSK) signal on a carrier on the transmitting medium (312U) from the node (316); the head end device (314) comprising: 1) head end receiving means (336) for receiving the OQPSK signal with an QPSK receiver to obtain a received signal, the head end receiving means (336) including a limiter circuit means (346) for hard limiting the received signal to obtain a limited signal within a defined range; and b) head end translating means (352) for transferring signals received at the head end device (314) of the transmitting medium (312U) to the receiving medium (312D); c) means (340) for transmitting continuously a class one, three-level partial response signal on a continuous carrier on the receiving medium (312D) from the head end device (314); and d) means (332) for modulating the continuous carrier with the bit pattern of the information when the bit pattern of the information is present and modulating the continuous carrier with a repetitive bit pattern when the bit pattern of the information is not present; and target node receiving means (372) for receiving the continuous carrier at the target node (318) on the receiving medium (312D), the target node receiving means (372) including: a) envelope detector means (374) for detecting the modulated continuous carrier; and b) analog to digital converting mens (376) for extracting the bit pattern of the information from the carrier by strobing the bit pattern in synchronism with a system clock.

Claim 11

A communication system (310) for transmitting information from a source node (316) to a target node (318) comprising: a head end device (314); a unidirectional transmitting medium (312U) coupling each node (316) in a source path to and terminating at the head end device (314); a unidirectional receiving medium (312D) originating from the head end device (314) and coupling to each target node (318); means (364) at the source node (316) for transmitting the information as an offset quadrature phase shift keyed (OQPSK) signal on a carrier on the transmitting medium (312U) from the node (316); the head end device (314) comprising: 1) head end receiving means (336) for receiving the OQPSK signal with an QPSK receiver to obtain a received signal, the head end receiving means (336) including a limiter circuit means (346) for hard limiting the received signal to obtain a limited signal within a defined range; and b) head end translating means (352) for transferring signals received at the head end device (314) of the transmitting medium (312U) to the receiving medium (312D); c) means (340) for transmitting continuously a class one, three-level partial response signal on a continuous carrier on the receiving medium (312D) from the head end device (314); and d) means (332) for modulating the continuous carrier with the bit pattern of the information when the bit pattern of the information is present and modulating the continuous carrier with a repetitive bit pattern when the bit pattern of the information is not present; and target node receiving means (372) for receiving the continuous carrier at the target node (318) on the receiving medium (312D), the target node receiving means (372) including: a) envelope detector means (374) for detecting the modulated continuous carrier; and b) analog to digital converting mens (376) for extracting the bit pattern of the information from the carrier by strobing the bit pattern in synchronism with a system clock.

Claim 12

A communication system as claimed in claim 6 or 7 comprising means (62;362) coupled to the first node (16;316) for digitizing a voice signal to produce the information.

Claim 13

A communication system as claimed in claim 6, 7 or 8 wherein the transmitting medium (12;312U) and the receiving medium (12D;312D) are separate frequency channels on a single physical medium (12;312) and the transmitting means (40;340) includes a frequency translator (58;358).

Claim 14

A communication system as claimed in claim 9 comprising a plurality of transmitting and receiving channels (12U,12D;312U,312D) on the physical medium (12;312), each of the nodes (16,18;316,318) having means for transmitting and receiving on more than one channel.

Claim 15

A communication system as claimed in any preceding claim wherein the head end device (14,314) comprises means (52;138;352;438) for aligning in time the bit pattern of the information to synchronize the bit pattern of the information with the repetitive bit pattern in order to allow extraction of bits at an optimised time.

Claim 20

A method as claimed in claim 12 or 13 comprising the step of aligning in time the bit pattern of the information at the head end (14;314) to synchronize the bit pattern of the information with the repetitive bit pattern in order to allow extraction of bits at an optimised time.

Claim 21

A method as claimed in claim 12, 13 or 14 comprising the step of digitizing a voice signal to produce the information.

Claim 22

A method as claimed in claim 12, 13, 14 or 15 wherein the signal transmitting step includes asynchronously transmitting the information in bursts.