Surface acoustic wave device, and demodulating apparatus and communication system using the surface acoustic wave device

Claim 2

A surface acoustic wave device, said device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; and wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave.

Claim 3

A surface acoustic wave device according to claim 1, wherein one of said input and output electrodes comprises a 2N number of taps (N is a natural number) and a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side.

Claim 4

A surface acoustic wave device according to claim 1, wherein one of said input and output electrodes comprises a 2N number of taps (N is a natural number) and a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side.

Claim 5

A surface acoustic wave device according to claim 1, wherein each of said taps comprises a comb electrode which includes at least one pair of electrode digits.

Claim 6

A surface acoustic wave device, said device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; and wherein one of said input and output electrodes comprises first and second electrodes which are arranged along a direction perpendicular to a propagation direction of the surface acoustic wave, said first and second electrodes respectively comprise a 2N number of taps (N is a natural number) which are equidistantly arranged in the propagation direction of the surface acoustic wave, said first electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side, said second electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side, and said first and second electrodes respectively satisfy an equation L+Δl=2V/A where L is a length of each of said first and second electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave.

Claim 7

A surface acoustic wave device, said device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; and wherein one of said input and output electrodes comprises first and second electrodes which are arranged along a direction perpendicular to a propagation direction of the surface acoustic wave, said first and second electrodes respectively comprise a 2N number of taps (N is a natural number) which are equidistantly arranged in the propagation direction of the surface acoustic wave, said first electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side, said second electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side, and said first and second electrodes respectively satisfy an equation L+Δl=2V/A where L is a length of each of said first and second electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave.

Claim 8

A surface acoustic wave device according to claim 5, wherein each of said taps comprises a comb electrode which includes at least one pair of electrode digits.

Claim 9

A demodulating device comprising: (a) a surface acoustic wave device for supplying a correlation signal based on an input signal modulated in accordance with data, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (b) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (c) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 10

A demodulating device comprising: (a) a surface acoustic wave device for supplying a correlation signal based on an input signal modulated in accordance with data, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (b) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (c) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 11

A demodulating device according to claim 7, wherein one of said input and output electrodes comprises a 2N number of taps (N is a natural number) and a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side.

Claim 12

A demodulating device according to claim 7, wherein one of said input and output electrodes comprises a 2N number of taps (N is a natural number) and a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side.

Claim 13

A demodulating device according to claim 7, wherein each of said taps comprises a comb electrode which includes at least one pair of electrode digits.

Claim 14

A demodulating device according to claim 7, wherein the input signal is a spread spectrum signal.

Claim 15

A demodulating device comprising: (a) a surface acoustic wave device for supplying a correlation signal based on an input signal modulated in accordance with data, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises first and second electrodes which are arranged along a direction perpendicular to a propagation direction of the surface acoustic wave, said first and second electrodes respectively comprise a 2N number of taps (N is a natural number) which are equidistantly arranged in the propagation direction of the surface acoustic wave, said first electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side, said second electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side, and said first and second electrodes respectively satisfy an equation L+Δl=2V/A where L is a length of each of said first and second electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (b) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (c) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 16

A demodulating device comprising: (a) a surface acoustic wave device for supplying a correlation signal based on an input signal modulated in accordance with data, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises first and second electrodes which are arranged along a direction perpendicular to a propagation direction of the surface acoustic wave, said first and second electrodes respectively comprise a 2N number of taps (N is a natural number) which are equidistantly arranged in the propagation direction of the surface acoustic wave, said first electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side, said second electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side, and said first and second electrodes respectively satisfy an equation L+Δl=2V/A where L is a length of each of said first and second electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (b) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (c) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 17

A demodulating device according to claim 12, wherein each of said taps comprises a comb electrode which includes at least one pair of electrode digits.

Claim 18

A demodulating device according to claim 12, wherein the input signal is a spread spectrum signal.

Claim 19

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a surface acoustic wave device for supplying a correlation signal based on the signal received by said receiver circuit, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the received signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (d) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (e) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 20

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a surface acoustic wave device for supplying a correlation signal based on the signal received by said receiver circuit, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the received signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (d) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (e) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 21

A communication system according to claim 15, wherein one of said input and output electrodes comprises a 2N number of taps (N is a natural number) and a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side.

Claim 22

A communication system according to claim 15, wherein one of said input and output electrodes comprises a 2N number of taps (N is a natural number) and a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side.

Claim 23

A communication system according to claim 15, wherein each of said taps comprises a comb electrode which includes at least one pair of electrode digits.

Claim 24

A communication system according to claim 15, wherein the input signal is a spread spectrum signal.

Claim 25

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a surface acoustic wave device for supplying a correlation signal based on the signal received by said receiver circuit, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the received signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises first and second electrodes which are arranged along a direction perpendicular to a propagation direction of the surface acoustic wave, said first and second electrodes respectively comprise a 2N number of taps (N is a natural number) which are equidistantly arranged in the propagation direction of the surface acoustic wave, said first electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side, said second electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side, and said first and second electrodes respectively satisfy an equation L+Δl=2V/A where L is a length of each of said first and second electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (d) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (e) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 26

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a surface acoustic wave device for supplying a correlation signal based on the signal received by said receiver circuit, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the received signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises first and second electrodes which are arranged along a direction perpendicular to a propagation direction of the surface acoustic wave, said first and second electrodes respectively comprise a 2N number of taps (N is a natural number) which are equidistantly arranged in the propagation direction of the surface acoustic wave, said first electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side, said second electrode is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side, and said first and second electrodes respectively satisfy an equation L+Δl=2V/A where L is a length of each of said first and second electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (d) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (e) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 27

A communication system according to claim 20, wherein each of said taps comprises a comb electrode which includes at least one pair of electrode digits.

Claim 28

A communication system according to claim 20, wherein the input signal is a spread spectrum signal.

Claim 29

A demodulating device comprising: (a) a branching device for dividing a signal modulated in accordance with data into first and second input signals; (b) a first surface acoustic wave device for supplying a first correlation signal based on the first input signal divided by said branching device, said first surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side, and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (c) a second surface acoustic wave device for supplying a second correlation signal based on the second input signal divided by said branching device, said second surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side, and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (d) a first detection circuit for envelope-detecting the first correlation signal supplied from said first surface acoustic wave device to supply an output; and (e) a second detection circuit for envelope-detecting the second correlation signal supplied from said second surface acoustic wave device to supply an output; and (f) a comparator circuit for comparing the outputs supplied from said first and second detection circuits.

Claim 30

A demodulating device comprising: (a) a branching device for dividing a signal modulated in accordance with data into first and second input signals; (b) a first surface acoustic wave device for supplying a first correlation signal based on the first input signal divided by said branching device, said first surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side, and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (c) a second surface acoustic wave device for supplying a second correlation signal based on the second input signal divided by said branching device, said second surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side, and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (d) a first detection circuit for envelope-detecting the first correlation signal supplied from said first surface acoustic wave device to supply an output; and (e) a second detection circuit for envelope-detecting the second correlation signal supplied from said second surface acoustic wave device to supply an output; and (f) a comparator circuit for comparing the outputs supplied from said first and second detection circuits.

Claim 31

A demodulating device according to claim 23, wherein each of said taps comprises a comb electrode which includes at least one pair of electrode digits.

Claim 32

A demodulating device according to claim 23, wherein the input signal is a spread spectrum signal.

Claim 33

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a branching device for dividing the signal received by said receiver circuit into first and second input signals; (d) a first surface acoustic wave device for supplying a first correlation signal based on the first input signal divided by said branching device, said first surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a 2N number of taps (n is a natural number) equidistantly arranged in a propagation direction of the surface acoustic wave, is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side, and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (e) a second surface acoustic wave device for supplying a second correlation signal based on the second input signal divided by said branching device, said second surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side, and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (e) a first detection circuit for envelope-detecting the first correlation signal supplied from said first surface acoustic wave device to supply an output; and (f) a second detection circuit for envelope-detecting the second correlation signal supplied from said second surface acoustic wave device to supply an output; and (g) a comparator circuit for comparing the outputs supplied from said first and second detection circuits.

Claim 34

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a branching device for dividing the signal received by said receiver circuit into first and second input signals; (d) a first surface acoustic wave device for supplying a first correlation signal based on the first input signal divided by said branching device, said first surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a 2N number of taps (n is a natural number) equidistantly arranged in a propagation direction of the surface acoustic wave, is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side, and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (e) a second surface acoustic wave device for supplying a second correlation signal based on the second input signal divided by said branching device, said second surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, is structured so that a signal polarity corresponding to the tap, which is the i-th one (i=1, 2, . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side, and satisfies an equation L+Δl=2V/A where L is a length of one of said input and output electrodes in the propagation direction, Δl is a length of a space between said taps, A is a transmission speed of the input signal and V is a propagation velocity of the surface acoustic wave; (e) a first detection circuit for envelope-detecting the first correlation signal supplied from said first surface acoustic wave device to supply an output; and (f) a second detection circuit for envelope-detecting the second correlation signal supplied from said second surface acoustic wave device to supply an output; and (g) a comparator circuit for comparing the outputs supplied from said first and second detection circuits.

Claim 35

A communication system according to claim 26, wherein each of said taps comprises a comb electrode which includes at least one pair of electrode digits.

Claim 36

A communication system according to claim 26, wherein the input signal is a spread spectrum signal.

Claim 37

A surface acoustic wave device, said device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; and wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second taps arranged at a predetermined distance in the propagation direction, and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer.

Claim 38

A surface acoustic wave device, said device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; and wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second taps arranged at a predetermined distance in the propagation direction, and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer.

Claim 39

A surface acoustic wave device according to claim 29, a signal polarity corresponding to said first tap is the same as a signal polarity corresponding to the second tap.

Claim 40

A surface acoustic wave device according to claim 29, a signal polarity corresponding to said first tap is opposite to a signal polarity corresponding to the second tap.

Claim 41

A surface acoustic wave device according to claim 29, wherein each of said taps of said one electrode, and said first and second taps respectively comprise a comb electrode which includes at least one pair of electrode digits.

Claim 42

A surface acoustic wave device, said device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second electrodes arranged in a direction perpendicular to the propagation direction, said first electrode comprises first and second taps arranged at a predetermined distance in the propagation direction, said second electrode comprises third and fourth taps arranged at a predetermined distance in the propagation diraction, and said first and second electrodes respectively satisfy an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer.

Claim 43

A surface acoustic wave device, said device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second electrodes arranged in a direction perpendicular to the propagation direction, said first electrode comprises first and second taps arranged at a predetermined distance in the propagation direction, said second electrode comprises third and fourth taps arranged at a predetermined distance in the propagation diraction, and said first and second electrodes respectively satisfy an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer.

Claim 44

A surface acoustic wave device according to claim 33, wherein each of said taps of said one electrode, and said first, second, third and fourth taps respectively comprise a comb electrode which includes at least one pair of electrode digits.

Claim 45

A demodulating device comprising: (a) a surface acoustic wave device for supplying a correlation signal based on an input signal modulated in accordance with data, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second taps arranged at a predetermined distance in the propagation direction, and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (b) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (c) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 46

A demodulating device comprising: (a) a surface acoustic wave device for supplying a correlation signal based on an input signal modulated in accordance with data, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second taps arranged at a predetermined distance in the propagation direction, and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (b) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (c) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 47

A demodulating device according to claim 35, wherein a signal polarity corresponding to said first tap is the same as a signal polarity corresponding to the second tap.

Claim 48

A demodulating device according to claim 35, a signal polarity corresponding to said first tap is opposite to a signal polarity corresponding to the second tap.

Claim 49

A demodulating device according to claim 35, wherein each of said taps of said one electrode, and said first and second taps respectively comprise a comb electrode which includes at least one pair of electrode digits.

Claim 50

A demodulating device according to claim 35, wherein the input signal is a spread spectrum signal.

Claim 51

A demodulating device comprising: (a) a surface acoustic wave device for supplying a correlation signal based on an input signal modulated in accordance with data, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second electrodes arranged in a direction perpendicular to the propagation direction, said first electrode comprises first and second taps arranged at a predetermined distance in the propagation direction, said second electrode comprises third and fourth taps arranged at a predetermined distance in the propagation diraction, and said first and second electrodes respectively satisfy an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (b) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (c) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 52

A demodulating device comprising: (a) a surface acoustic wave device for supplying a correlation signal based on an input signal modulated in accordance with data, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with an input signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second electrodes arranged in a direction perpendicular to the propagation direction, said first electrode comprises first and second taps arranged at a predetermined distance in the propagation direction, said second electrode comprises third and fourth taps arranged at a predetermined distance in the propagation diraction, and said first and second electrodes respectively satisfy an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (b) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (c) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 53

A demodulating device according to claim 40, wherein each of said taps of said one electrode, and said first, second, third and fourth taps respectively comprise a comb electrode which includes at least one pair of electrode digits.

Claim 54

A demodulating device according to claim 40, wherein the input signal is a spread spectrum signal.

Claim 55

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a surface acoustic wave device for supplying a correlation signal based on the signal received by said receiver circuit, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the received signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second taps arranged at a predetermined distance in the propagation direction, and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (d) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (e) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 56

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a surface acoustic wave device for supplying a correlation signal based on the signal received by said receiver circuit, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the received signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second taps arranged at a predetermined distance in the propagation direction, and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (d) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (e) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 57

A communication system according to claim 43, wherein a signal polarity corresponding to said first tap is the same as a signal polarity corresponding to the second tap.

Claim 58

A communication system according to claim 43, wherein, wherein a signal polarity corresponding to said first tap is opposite to a signal polarity corresponding to said second tap.

Claim 59

A communication system according to claim 43, wherein each of said taps of said one electrode, and said first and second taps respectively comprise a comb electrode which includes at least one pair of electrode digits.

Claim 60

A communication system according to claim 43, wherein the input signal is a spread spectrum signal.

Claim 61

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a surface acoustic wave device for supplying a correlation signal based on the signal received by said receiver circuit, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the received signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second electrodes arranged in a direction perpendicular to the propagation direction, said first electrode comprises first and second taps arranged at a predetermined distance in the propagation direction, said second electrode comprises third and fourth taps arranged at a predetermined distance in the propagation diraction, and said first and second electrodes respectively satisfy an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (d) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (e) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 62

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a surface acoustic wave device for supplying a correlation signal based on the signal received by said receiver circuit, said surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the received signal, said input electrode being formed on said substrate; and an output electrode for receiving the surface acoustic wave and supplying the correlation signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second electrodes arranged in a direction perpendicular to the propagation direction, said first electrode comprises first and second taps arranged at a predetermined distance in the propagation direction, said second electrode comprises third and fourth taps arranged at a predetermined distance in the propagation diraction, and said first and second electrodes respectively satisfy an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (d) a detection circuit for envelope-detecting the correlation signal supplied from said surface acoustic wave device to supply an output; and (e) a data judging circuit for judging the data based on the output from said detection circuit.

Claim 63

A communication system according to claim 48, wherein each of said taps of said one electrode, and said first, second, third and fourth taps respectively comprise a comb electrode which includes at least one pair of electrode digits.

Claim 64

A communication system according to claim 48, wherein the input signal is a spread spectrum signal.

Claim 65

A demodulating device comprising: (a) a branching device for dividing a signal modulated in accordance with data into first and second input signals; (b) a first surface acoustic wave device for supplying a first correlation signal based on the first input signal divided by said branching device, said first surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second taps arranged at a predetermined distance in the propagation direction, a signal polarity corresponding to said first tap is the same as a signal polarity corresponding to said second tap, and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (c) a second surface acoustic wave device for supplying a second correlation signal based on the second input signal divided by said branching device, said second surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises third and fourth taps arranged at a predetermined distance in the propagation direction, a signal polarity corresponding to said third tap is opposite to a signal polarity corresponding to said fourth tap, and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said third and fourth taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (d) a first detection circuit for envelope-detecting the first correlation signal supplied from said first surface acoustic wave device to supply an output; and (e) a second detection circuit for envelope-detecting the second correlation signal supplied from said second surface acoustic wave device to supply an output; and (f) a comparator circuit for comparing the outputs supplied from said first and second detection circuits.

Claim 66

A demodulating device comprising: (a) a branching device for dividing a signal modulated in accordance with data into first and second input signals; (b) a first surface acoustic wave device for supplying a first correlation signal based on the first input signal divided by said branching device, said first surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second taps arranged at a predetermined distance in the propagation direction, a signal polarity corresponding to said first tap is the same as a signal polarity corresponding to said second tap, and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (c) a second surface acoustic wave device for supplying a second correlation signal based on the second input signal divided by said branching device, said second surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises third and fourth taps arranged at a predetermined distance in the propagation direction, a signal polarity corresponding to said third tap is opposite to a signal polarity corresponding to said fourth tap, and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said third and fourth taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (d) a first detection circuit for envelope-detecting the first correlation signal supplied from said first surface acoustic wave device to supply an output; and (e) a second detection circuit for envelope-detecting the second correlation signal supplied from said second surface acoustic wave device to supply an output; and (f) a comparator circuit for comparing the outputs supplied from said first and second detection circuits.

Claim 67

A demodulating device according to claim 51, wherein each of said taps of said one electrode, and said first, second, third and fourth taps comprise a comb electrode which includes at least one pair of electrode digits.

Claim 68

A demodulating device according to claim 51, wherein the input signal is a spread spectrum signal.

Claim 69

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a branching device for dividing the signal received by said receiver circuit into first and second input signals; (d) a first surface acoustic wave device for supplying a first correlation signal based on the first input signal divided by said branching device, said first surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second taps arranged at a predetermined distance in the propagation direction, a signal polarity corresponding to said first tap is the same as a signal polarity corresponding to said second tap and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (e) a second surface acoustic wave device for supplying a second correlation signal based on the second input signal divided by said branching device, said second surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises third and fourth taps arranged at a predetermined distance in the propagation direction, a signal polarity corresponding to said third tap is opposite to a signal polarity corresponding to said fourth tap and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said third and fourth taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (e) a first detection circuit for envelope-detecting the first correlation signal supplied from said first surface acoustic wave device to supply an output; and (f) a second detection circuit for envelope-detecting the second correlation signal supplied from said second surface acoustic wave device to supply an output; and (g) a comparator circuit for comparing the outputs supplied from said first and second detection circuits.

Claim 70

A communication system comprising: (a) a transmitter for transmitting a signal modulated in accordance with data; (b) a receiver circuit for receiving the signal transmitted from said transmitter; (c) a branching device for dividing the signal received by said receiver circuit into first and second input signals; (d) a first surface acoustic wave device for supplying a first correlation signal based on the first input signal divided by said branching device, said first surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises first and second taps arranged at a predetermined distance in the propagation direction, a signal polarity corresponding to said first tap is the same as a signal polarity corresponding to said second tap and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said first and second taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (e) a second surface acoustic wave device for supplying a second correlation signal based on the second input signal divided by said branching device, said second surface acoustic wave device comprising: a piezoelectric substrate; an input electrode for generating a surface acoustic wave propagated in a predetermined direction, in accordance with the input signal, said input electrode being formed on said substrate; and an output electrode for converting the surface acoustic wave to an electric signal, said output electrode being formed on said substrate; wherein one of said input and output electrodes comprises a plurality of taps equidistantly arranged in a propagation direction of the surface acoustic wave, the other one of said input and output electrodes comprises third and fourth taps arranged at a predetermined distance in the propagation direction, a signal polarity corresponding to said third tap is opposite to a signal polarity corresponding to said fourth tap and said the other electrode satisfies an equation D=nV/A where D is a distance between center lines of said third and fourth taps in the propagation direction, A is a transmission speed of the input signal, V is a propagation velocity of the surface acoustic wave and n is a positive integer; (e) a first detection circuit for envelope-detecting the first correlation signal supplied from said first surface acoustic wave device to supply an output; and (f) a second detection circuit for envelope-detecting the second correlation signal supplied from said second surface acoustic wave device to supply an output; and (g) a comparator circuit for comparing the outputs supplied from said first and second detection circuits.

Claim 71

A communication system according to claim 54, wherein each of said taps of said one electrode, and said first, second, third and fourth taps respectively comprise a comb electrode which includes at least one pair of electrode digits.

Claim 72

A communication system according to claim 54, wherein the input signal is a spread spectrum signal.

Claim 75

A method for demodulating data according to claim 57, wherein the step for demodulating data comprises a step for envelope-detecting the electric signal and a step for judging the data from the envelope-detected signal.

Claim 76

A method for demodulating data according to claim 57, wherein the input signal is a spread spectrum signal.

Claim 77

A method for demodulating data according to claim 57, wherein the input signal is a differential phase-shifted keyed signal.

Claim 78

A method for demodulating data according to claim 57, wherein one of said input and output electrodes comprises 2N taps (N is a natural number), and a signal polarity corresponding to the tap, which is the i-th one (i=1, 2 . . . , N) counted from one side, is the same as a signal polarity corresponding to the (N+i)-th tap counted from the same side.

Claim 79

A method for demodulating data according to claim 57, wherein one of said input and output electrodes comprises 2N taps (N is a natural number), and a signal polarity corresponding to the tap, which is the i-th one (i=1, 2 . . . , N) counted from one side, is opposite to a signal polarity corresponding to the (N+i)-th tap counted from the same side.

Claim 80

A method for demodulating data according to claim 57, wherein each of said taps comprises a comb electrode which includes at least one pair of electrode digits.

Claim 83

A method for demodulating data according to claim 64, wherein the step for demodulating the data comprises a step for envelope-detecting the electric signal and a step for judging the data from the envelope-detected signal.

Claim 84

A method for demodulating data according to claim 64, wherein the input signal is a spread spectrum signal.

Claim 85

A method for demodulating data according to claim 64, wherein the input signal is a differential phase-shifted keyed signal.

Claim 86

A method for demodulating data according to claim 64, wherein a signal polarity corresponding to said first tap is the same as a signal polarity corresponding to said second tap.

Claim 87

A method for demodulating data according to claim 64, wherein a signal polarity corresponding to said first tap is opposite to a signal polarity corresponding to said second tap.

Claim 88

A method for demodulating data according to claim 64, wherein each of said taps of said one electrode, and said first and second taps of the other electrode respectively comprise a comb electrode which includes at least one pair of electrode digits.