Signal transmission system

Claim 2

A signal transmission system comprising: a modulator for producing m signal points, where m is an integer, in a signal space diagram through modulation of a carrier wave using an input signal; and a transmitter for transmitting a modulated signal, in which the main procedure includes receiving the input signal containing a first data stream of n values and a second data stream, dividing the m signal points into n signal point groups, assigning n values of the first data stream to the n signal point groups respectively, and assigning data of the second data stream to the signal points of each signal point group.

Claim 3

A signal transmission system according to Claim 1, wherein the first and second data streams are two, low and high, frequency band components of a video or audio signal respectively.

Claim 4

A signal transmission system according to Claim 1, wherein during transmission and reception of both the first and second data streams of the signal, the second data stream can be canceled transmission or reception when the error rate at transmission becomes high while the first data stream continues to be transmitted.

Claim 5

A signal transmission system according to Claim 1, wherein the signal points are shifted to other positions in the signal space diagram so that one of them which is located at a nearest position to the origin point of the I-axis and Q-axis coordinates of the diagram, is spaced S8 from each axis where δ is the distance between the nearest signal point and the I- or Q-axis and S is the length of shift which is more than 1.

Claim 6

A signal transmission system comprising: a demodulator for demodulating a received QAM signal representing P signal points in a signal space diagram; and an output, in which the main procedure includes dividing the P signal points into n signal point groups, demodulating a first data stream of which n values are assigned to the n signal point groups, and demodulating a second data stream of which P/n values are assigned to P/n signal points of each signal point group for reconstruction of data of the first and second data streams.

Claim 7

A signal transmission system comprising: a demodulator for demodulating a received QAM signal representing P signal points in a signal space diagram; and an output, in which the main procedure includes dividing the P signal points into n signal point groups, demodulating a first data stream of which n values are assigned to the n signal point groups, and demodulating a second data stream of which P/n values are assigned to P/n signal points of each signal point group for reconstruction of data of the first and second data streams.

Claim 8

A signal transmission system according to Claim 5, wherein the first and second data streams represent two, low and high, frequency band components of a video signal respectively.

Claim 9

A signal transmission system according to Claim 5, wherein during reception of both the first and second data streams of the signal, the second data stream can be canceled when the error rate becomes high while the first data stream continues to be intercepted.

Claim 10

A signal transmission system according to Claim 5, further comprising a carrier wave reproducer in which a carrier wave is reproduced from the received signal by 16x multiplication of a frequency of the received signal.

Claim 11

A signal transmission system according to Claim 5, wherein the signal points of QAM are shifted to other positions in the signal space diagram so that one of them which is located at a nearest position to the origin point of the I-axis and Q-axis coordinates of the diagram, is spaced S8 from each axis where δ is the distance between the nearest signal point and the I- or Q-axis and S is the length of shift which is more than 1.

Claim 12

A signal transmission system comprising: a transmitter having a signal input circuit, a modulator circuit for producing m signal points in a signal space diagram through modulation of a carrier wave using an input signal fed from the signal input circuit, and a transmitter circuit for transmitting a modulated signal, in which a main procedure includes receiving the input signal containing a first data stream of n values and a second data stream, dividing the m signal points into n signal point groups, assigning n values of the first data stream to the n signal point groups respectively, and assigning data of the second data stream to the signal points of each signal point group; and a receiver having an input circuit for reception of the modulated signal from the transmitter, a demodulator circuit for demodulating a QAM modulated signal representing P signal points in a signal space diagram, and an output circuit, in which the main procedure includes dividing the P signal points into signal point groups, demodulating the first data stream of which n values are assigned to the n signal point groups, and demodulating the second data stream of which P/n values are assigned to P/n signal points of each signal point group for reconstruction of data of the first and second data streams.

Claim 13

A signal transmission system comprising: a transmitter having a signal input circuit, a modulator circuit for producing m signal points in a signal space diagram through modulation of a carrier wave using an input signal fed from the signal input circuit, and a transmitter circuit for transmitting a modulated signal, in which a main procedure includes receiving the input signal containing a first data stream of n values and a second data stream, dividing the m signal points into n signal point groups, assigning n values of the first data stream to the n signal point groups respectively, and assigning data of the second data stream to the signal points of each signal point group; and a receiver having an input circuit for reception of the modulated signal from the transmitter, a demodulator circuit for demodulating a QAM modulated signal representing P signal points in a signal space diagram, and an output circuit, in which the main procedure includes dividing the P signal points into signal point groups, demodulating the first data stream of which n values are assigned to the n signal point groups, and demodulating the second data stream of which P/n values are assigned to P/n signal points of each signal point group for reconstruction of data of the first and second data streams.

Claim 14

A signal transmission system according to Claim 10, wherein the first and second data streams represent two, low and high, frequency band components of a video signal respectively.

Claim 15

A signal transmission system according to Claim 10, wherein the signal points of QAM are shifted to other positions in the signal space diagram so that one of them which is located at a nearest position to the origin point of the I-axis and Q-axis coordinates of the diagram, is spaced S8 from each axis where δ is the distance between the nearest signal point and the I- or Q-axis and S is the length of shift which is more than 1.

Claim 16

A signal transmission system comprising: a modulating means for modulating a carrier wave with an input signal to produce m signal points, where m is an integer, on a signal space diagram; transmitting means for transmitting the modulated signal; and means for changing or modulating positions of the signal points with a part of the input signal.

Claim 17

A signal transmission system comprising: a modulating means for modulating a carrier wave with an input signal to produce m signal points, where m is an integer, on a signal space diagram; transmitting means for transmitting the modulated signal; and means for changing or modulating positions of the signal points with a part of the input signal.