# Patent

## Title
Spread spectrum communication device and communication system

## Abstract

A structure of a spectrum spreading communication device which solves the problem with the conventional spectrum spreading communication using Barker codes, etc., and limits the rise of the side-lobe of a correctional signal independently of the order of information codes by use of a code sequence having a code length of at least 14. The spectrum spreading communication device uses a pseudo-noise code having code length of at least 14 and a self-correlation side-lobe of not greater than 3 as a pseudo-noise code of a direct spreading communication device which uses the pseudo-noise codes whose polarities are inverted so as to deal with also digital information. Thus, even when the pseudo-noise code length is 14 or more, the side-lobe of the correction coefficient can be restricted. Accordingly, the error rate of the spectrum spreading communication device is reduced and the processing gain is improved.

## Background
The present application is a continuation of application Ser. No. 09/558,373, filed Apr. 26, 2000 now U.S. Pat. No. 6,697,418; which is a continuation of application Ser. No. 08/875,182, filed Jul. 21, 1997, now U.S. Pat. No. 6,134,264, the contents of which are incorporated herein by reference.


BACKGROUND OF THE INVENTION
The present invention relates to surface acoustic wave devices and communication devices.
In conventional spread spectrum communication devices using the direct spreading method, a Barker code was used as a pseudo noise code as described in 1985 ULTRASONICS SYMPOSIUM proceedings, pp. 145-148, for example. It is known that this code does not depend on the arrangement of an information code sequence and this code has an auto-correlation side lobe of 1.
The Barker code has been found with the code length of 13 or less. The Barker code has not been found with a code length exceeding it. In the case where a processing gain of a code length of at least 14 was required, therefore, a code other than the Barker code, such as the longest code sequence was used. In these code sequences, however, a large side lobe rise is caused when the sign of the information code is inverted. In general, therefore, the error rate is increased.
An object of the present invention is to solve the above described problem and provide a novel structure of a spread spectrum communication device which uses a code sequence having a code length of at least 14, which does not depend on the arrangement of the information code, and which suppresses the side lobe rise of correlation signals.
SUMMARY OF THE INVENTION
The above described object can be achieved by employing a code sequence used by the present invention, i.e., a code shown in TABLES 1 through 9 as the pseudo noise code for spreading the power density spectrum of an input signal.
It has been confirmed by calculation conducted by the present inventors that the code shown in TABLES 1 through 9 has an auto-correlation coefficient side lobe of 3 or less. If this code is used, therefore, there is obtained a novel spread spectrum communication device and communication system which has a processing gain having an auto-correlation coefficient side lobe of at least 14, which does not depend on the arrangement of the information code, which suppresses the side lobe rise of the correlation signal, and which makes the error rate small. In addition, a surface acoustic wave device utilizing this characteristic is obtained.
The present invention relates to a novel code having a processing gain with a code length of at least 14 and an auto-correlation side lobe of 3 or less. The code length is determined in some cases by using harmonics of the crystal (oscillation frequency in the case where a frequency multiplier is used). In other cases, the code length is generated independently of the clock frequency of the baseband digital circuit.
It is now assumed that the code length is determined by using harmonics of the crystal. If harmonics are generated by distorting the oscillation waveform of the clock frequency in order to make harmonic components large, for example, only odd-number components included in harmonic components are typically generated. If its odd-number components are used as the clock of pseudo noise code generator, therefore, a value obtained by dividing the clock of the pseudo noise code generator by the clock frequency of the baseband digital circuit, i.e., the code length is obtained. To be concrete, an odd-numbered code length such as 15, 17, 19, . . . is obtained.
In the case where the obtained odd-numbered code length is applied to a spread spectrum communication-device, two code lengths are combined and used in some cases. To be concrete, it is a result of multiplication of odd-numbered code lengths. A value of at least 14 such as 15, 21, 25, 27, . . . is used as the code length.
In the case where the code length is generated independently of the clock frequency of the baseband digital circuit, it doesn't matter at all whether the code length is even-numbered or odd-numbered and consequently values of at least 14, i.e., values 14, 15, 16, 17, . . . are obtained.
In either case, a pseudo noise code formed by a large number of combinations in respective code lengths is present. Out of them, the present inventors found a novel code which is 3 or less in auto-correlation side lobe and which is effective as the pseudo noise code used for spreading the power density spectrum of an input signal. The present inventors also found a novel pseudo noise generator capable of executing spreading (or de-spreading) of the power density spectrum of an input signal by using those codes.
The following TABLES 1 through 9 show the pseudo noise code concerning the present invention.







TABLE 1







(n = 14)













max. corr.
max. corr.



number
bj
(forward)
(back)
dc level














202
00000011001010
2
6
−6


332
00000101001100
2
6
−6


404
00000110010100
2
8
−6


405
00000110010101
2
6
−4


410
00000110011010
2
10
−4


470
00000111010110
2
10
−2


665
00001010011001
2
10
−4


691
00001010110011
2
10
−2


811
00001100101011
2
10
−2


821
00001100110101
2
10
−2


1883
00011101011011
2
10
2


2375
00100101000111
2
10
−2


2656
00101001100000
2
8
−6


2767
00101011001111
2
10
2


3232
00110010100000
2
6
−6


3247
00110010101111
2
10
2


3322
00110011111010
2
10
2


4021
00111110110101
2
10
4


4622
01001000001110
2
10
−4


5145
01010000011001
2
6
−4


5251
01010010000011
2
10
−4


5312
01010011000000
2
6
−6


5313
01010011000001
2
8
−4


5327
01010011001111
2
10
2


5535
01010110011111
2
6
4


5728
01011001100000
2
10
−4


5758
01011001111110
2
10
4


6092
01011111001100
2
10
2


6118
01011111100110
2
10
4


6575
01100110101111
2
10
4


6645
01100111110101
2
6
4


6650
01100111111010
2
10
4


6880
01101011100000
2
10
−2


7186
01110000010010
2
10
−4


7989
01111100110101
2
8
4


8090
01111110011010
2
10
4


8293
10000001100101
2
10
−4


8394
10000011001010
2
8
−4


9197
10001111101101
2
10
4


9503
10010100011111
2
10
2


9733
10011000000101
2
10
−4


9738
10011000001010
2
6
−4


9808
10011001010000
2
10
−4


10265
10100000011001
2
10
−4


10291
10100000110011
2
10
−2


10625
10100110000001
2
10
−4


10655
10100110011111
2
10
4


10848
10101001100000
2
6
−4


11056
10101100110000
2
10
−2


11070
10101100111110
2
8
4


11071
10101100111111
2
6
6


11132
10101101111100
2
10
4


11238
10101111100110
2
6
4


11761
10110111110001
2
10
4


12362
11000001001010
2
10
−4


13061
11001100000101
2
10
−2


13136
11001101010000
2
10
−2


13151
11001101011111
2
6
6


13616
11010100110000
2
10
−2


13727
11010110011111
2
8
6


14008
11011010111000
2
10
2


14500
11100010100100
2
10
−2


15562
11110011001010
2
10
2


15572
11110011010100
2
10
2


15692
11110101001100
2
10
2


15718
11110101100110
2
10
4


15913
11111000101001
2
10
2


15973
11111001100101
2
10
4


15978
11111001101010
2
6
4


15979
11111001101011
2
8
6


16051
11111010110011
2
6
6


16181
11111100110101
2
6
6
















TABLE 2







(n = 15)













max. corr.
max. corr.



number
bj
(forward)
(back)
dc level














202
000000011001010
3
7
−7


332
000000101001100
3
7
−7


345
000000101011001
3
7
−5


394
000000110001010
3
7
−7


404
000000110010100
3
9
−7


405
000000110010101
3
7
−5


410
000000110011010
3
11
−5


618
000001001101010
3
7
−5


652
000001010001100
3
11
−7


664
000001010011000
3
11
−7


665
000001010011001
3
11
−5


678
000001010100110
3
7
−5


691
000001010110011
3
7
−3


710
000001011000110
3
11
−5


718
000001011001110
3
7
−3


808
000001100101000
3
11
−7


809
000001100101001
3
11
−5


810
000001100101010
3
7
−5


811
000001100101011
3
9
−3


821
000001100110101
3
7
−3


922
000001110011010
3
11
−3


1140
000010001110100
3
11
−5


1221
000010011000101
3
11
−5


1299
000010100010011
3
11
−5


1305
000010100011001
3
11
−5


1356
000010101001100
3
11
−5


1380
000010101100100
3
11
−5


1610
000011001001010
3
11
−5


1620
000011001010100
3
11
−5


1642
000011001101010
3
11
−3


1672
000011010001000
3
11
−7


2152
000100001101000
3
11
−7


2224
000100010110000
3
11
−7


2228
000100010110100
3
11
−5


2281
000100011101001
3
11
−3


2579
000101000010011
3
11
−5


2587
000101000011011
3
11
−3


2656
000101001100000
3
11
−7


2824
000101100001000
3
11
−7


3232
000110010100000
3
11
−7


3748
000111010100100
3
9
−3


3821
000111011101101
3
9
3


4188
001000001011100
3
11
−5


4305
001000011010001
3
11
−5


4419
001000101000011
3
11
−5


4449
001000101100001
3
11
−5


4792
001001010111000
3
9
−3


4874
001001100001010
3
7
−5


4944
001001101010000
3
11
−5


5079
001001111010111
3
11
3


5139
001010000010011
3
11
−5


5145
001010000011001
3
11
−5


5312
001010011000000
3
9
−7


5313
001010011000001
3
11
−5


5424
001010100110000
3
11
−5


5535
001010110011111
3
9
3


5619
001010111110011
3
11
3


5649
001011000010001
3
11
−5


5768
001011010001000
3
11
−5


5904
001011100010000
3
11
−5


6154
001100000001010
3
7
−7


6165
001100000010101
3
7
−5


6187
001100000101011
3
11
−3


6304
001100010100000
3
11
−7


6405
001100100000101
3
11
−5


6464
001100101000000
3
7
−7


6465
001100101000001
3
11
−5


6480
001100101010000
3
11
−5


6495
001100101011111
3
7
3


6645
001100111110101
3
11
3


6922
001101100001010
3
11
−3


7087
001101110101111
3
11
5


7127
001101111010111
3
11
5


7147
001101111101011
3
11
5


7428
001110100000100
3
11
−5


7867
001111010111011
3
11
5


7901
001111011011101
3
11
5


7989
001111100110101
3
11
3


8369
010000010110001
3
11
−5


8377
010000010111001
3
11
−3


8394
010000011001010
3
11
−5


8610
010000110100010
3
11
−5


8730
010001000011010
3
11
−5


8734
010001000011110
3
11
−3


8771
010001001000011
3
11
−5


8898
010001011000010
3
11
−5


9230
010010000001110
3
9
−5


9287
010010001000111
3
9
−3


9738
010011000001010
3
11
−5


10252
010100000001100
3
7
−7


10265
010100000011001
3
7
−5


10278
010100000100110
3
11
−5


10290
010100000110010
3
11
−5


10291
010100000110011
3
11
−3


10340
010100001100100
3
7
−5


10348
010100001101100
3
11
−3


10432
010100011000000
3
7
−7


10544
010100100110000
3
11
−5


10624
010100110000000
3
7
−7


10625
010100110000001
3
7
−7


10626
010100110000010
3
11
−5


10627
010100110000011
3
11
−3


10655
010100110011111
3
7
3


10848
010101001100000
3
7
−5


11040
010101100100000
3
7
−5


11056
010101100110000
3
11
−3


11070
010101100111110
3
9
3


11071
010101100111111
3
7
5


11238
010101111100110
3
7
3


11251
010101111110011
3
7
5


11298
010110000100010
3
11
−5


11456
010110011000000
3
11
−5


11488
010110011100000
3
11
−3


11518
010110011111110
3
11
5


11887
010111001101111
3
11
5


11998
010111011011110
3
11
5


12211
010111110110011
3
11
5


12217
010111110111001
3
11
5


12238
010111111001110
3
11
5


12262
010111111100110
3
11
5


12549
011000100000101
3
11
−5


12609
011000101000001
3
11
−5


12669
011000101111101
3
11
3


12704
011000110100000
3
11
−5


12810
011001000001010
3
11
−5


12929
011001010000001
3
11
−5


12960
011001010100000
3
7
−5


12991
011001010111111
3
7
5


13151
011001101011111
3
11
5


13231
011001110101111
3
11
5


13290
011001111101010
3
7
3


13291
011001111101011
3
11
5


13301
011001111110101
3
7
5


13306
011001111111010
3
11
5


13329
011010000010001
3
11
−5


13431
011010001110111
3
11
3


13727
011010110011111
3
11
5


14254
011011110101110
3
11
5


14354
011100000010010
3
9
−5


14717
011100101111101
3
11
5


14752
011100110100000
3
7
−3


14842
011100111111010
3
11
5


14971
011101001111011
3
11
5


15094
011101011110110
3
11
5


15307
011101111001011
3
11
5


15337
011101111101001
3
11
5


15394
011110000100010
3
11
−3


15547
011110010111011
3
11
5


15802
011110110111010
3
11
5


15978
011111001101010
3
9
3


15979
011111001101011
3
11
5


16051
011111010110011
3
11
5


16057
011111010111001
3
11
5


16181
011111100110101
3
9
5


16217
011111101011001
3
11
5


16282
011111110011010
3
11
5


16485
100000001100101
3
11
−5


16550
100000010100110
3
11
−5


16586
100000011001010
3
9
−5


16710
100000101000110
3
11
−5


16716
100000101001100
3
11
−5


16788
100000110010100
3
11
−5


16789
100000110010101
3
9
−3


16965
100001001000101
3
11
−5


17220
10001101000100
3
11
−5


17373
100001111011101
3
11
3


17430
100010000010110
3
11
−5


17460
100010000110100
3
11
−5


17673
100010100001001
3
11
−5


17796
100010110000100
3
11
−5


17925
100011000000101
3
11
−5


18015
100011001011111
3
7
3


18050
100011010000010
3
11
−5


18413
100011111101101
3
9
5


18513
100100001010001
3
11
−5


19040
100101001100000
3
11
−5


19336
100101110001000
3
11
−3


19438
100101111101110
3
11
5


19461
100110000000101
3
11
−5


19466
100110000001010
3
7
−5


19476
100110000010100
3
11
−5


19477
100110000010101
3
7
−3


19536
100110001010000
3
11
−5


19616
100110010100000
3
11
−5


19776
100110101000000
3
7
−5


19807
100110101011111
3
7
5


19838
100110010111110
3
11
5


19957
100110111110101
3
11
5


20063
100111001011111
3
11
5


20098
100111010000010
3
11
−3


20158
100111010111110
3
11
5


20218
100111011111010
3
11
5


20505
10100000000101
3
11
−5


20529
101000000110001
3
11
−5


20550
101000001000110
3
11
−5


20556
101000001001100
3
11
−5


20769
101000100100001
3
11
−5


20880
101000110010000
3
11
−5


21249
101001100000001
3
11
−5


21279
101001100011111
3
11
3


21311
101001100111111
3
11
5


21469
101001111011101
3
11
5


21516
101010000001100
3
7
−5


21529
101010000011001
3
7
−3


21696
101010011000000
3
7
−5


21697
101010011000001
3
9
−3


21711
101010011001111
3
11
3


21727
101010011011111
3
7
5


21919
101010110011111
3
7
5


22112
101011001100000
3
7
−3


22140
101011001111100
3
11
3


22141
101011001111101
3
11
5


22142
101011001111110
3
9
5


22143
101011001111111
3
7
7


22223
101011011001111
3
11
5


22335
101011100111111
3
7
7


22419
101011110010011
3
11
3


22427
101011110011011
3
7
5


22476
101011111001100
3
11
3


22477
101011111001101
3
11
5


22489
101011111011001
3
11
5


22502
10101111110110
3
7
5


22515
101011111110011
3
7
7


23029
101100111110101
3
11
5


23480
101101110111000
3
9
3


23537
101101111110001
3
9
5


23869
101110100111101
3
11
5


23996
101110110111100
3
11
5


24033
101110111100001
3
11
3


24037
101110111100101
3
11
5


24157
101111001011101
3
11
5


24373
101111100110101
3
11
5


24390
101111101000110
3
11
3


24398
101111101001110
3
11
5


24778
110000011001010
3
11
−3


24866
110000100100010
3
11
−5


24900
110000101000100
3
11
−5


25339
110001011111011
3
11
5


25620
110010000010100
3
11
−5


25640
110010000101000
3
11
−5


25680
110010001010000
3
11
−5


25845
110010011110101
3
11
3


26122
110011000001010
3
11
−3


26272
110011010100000
3
7
−3


26287
110011010101111
3
11
5


26302
110011010111110
3
11
5


26303
110011010111111
3
7
7


26362
110011011111010
3
11
5


26463
110011101011111
3
11
7


26580
110011111010100
3
11
3


26602
110011111101010
3
7
5


26613
110011111110101
3
7
7


26863
110100011101111
3
11
5


26999
110100101110111
3
11
5


27118
110100111101110
3
11
5


27148
110101000001100
3
11
−3


27232
110101001100000
3
9
−3


27343
110101011001111
3
11
5


27454
110101100111110
3
11
5


27455
110101100111111
3
9
7


27622
110101111100110
3
11
5


27628
110101111101100
3
11
5


27688
110110000101000
3
11
−3


27823
110110010101111
3
11
5


27893
110110011110101
3
7
5


27975
110110101000111
3
9
3


28318
110111010011110
3
11
5


28348
110111010111100
3
11
5


28462
110111100101110
3
11
5


28579
110111110100011
3
11
5


28946
111000100010010
3
9
−3


29019
111000101011011
3
9
3


29535
111001101011111
3
11
7


29943
111010011110111
3
11
7


30111
111010110011111
3
11
7


30180
111010111100100
3
11
3


30188
111010111101100
3
11
5


30486
111011100010110
3
11
3


30539
111011101001011
3
11
5


30543
111011101001111
3
11
7


30615
111011110010111
3
11
7


31095
111100101110111
3
11
7


31125
111100110010101
3
11
3


31147
111100110101011
3
11
5


31157
111100110110101
3
11
5


31387
111101010011011
3
11
5


31411
111101010110011
3
11
5


31462
111101011100110
3
11
5


31468
111101011101100
3
11
5


31546
111101100111010
3
11
5


31627
111101110001011
3
11
5


31845
111110001100101
3
11
3


31946
111110011001010
3
7
3


31956
111110011010100
3
9
3


31957
111110011010101
3
7
5


31958
111110011010110
3
11
5


31959
111110011010111
3
11
7


32049
111110100110001
3
7
3


32057
111110100111001
3
11
5


32076
111110101001100
3
7
3


32089
111110101011001
3
7
5


32102
111110101100110
3
11
5


32103
111110101100111
3
11
7


32115
111110101110011
3
11
7


32149
111110110010101
3
7
5


32357
111111001100101
3
11
5


32362
111111001101010
3
7
5


32363
111111001101011
3
9
7


32373
111111001110101
3
7
7


32422
111111010100110
3
7
5


32435
111111010110011
3
7
7


32565
111111100110101
3
7
7
















TABLE 3







(n = 17)













max. corr.
max. corr.



number
bj
(forward)
(back)
dc level














2931
00000101101110011
3
9
−1


3253
00000110010110101
3
9
−3


3286
00000110011010110
3
9
−3


3685
00000111001100101
3
13
−3


3693
00000111001101101
3
11
−1


3893
00000111100110101
3
9
−1


3929
00000111101011001
3
11
−1


5555
00001010110110011
3
9
−1


5838
00001011011001110
3
11
−1


6443
00001100100101011
3
9
−3


6581
00001100110110101
3
13
−1


6775
00001101001110111
3
13
1


6877
00001101011011101
3
9
1


7386
00001110011011010
3
11
−1


7642
00001110111011010
3
9
1


7859
00001111010110011
3
9
1


7901
00001111011011101
3
11
3


7917
00001111011101101
3
13
3


9039
00010001101001111
3
13
−1


9125
00010001110100101
3
11
−3


9171
00010001111010011
3
9
−1


9189
00010001111100101
3
9
−1


11111
00010101101100111
3
9
1


12121
00010111101011001
3
9
1


12887
00011001001010111
3
9
−1


14773
00011100110110101
3
11
1


15269
00011101110100101
3
13
1


15284
00011101110110100
3
9
1


15716
00011110101100100
3
11
−1


15718
00011110101100110
3
9
1


16217
00011111101011001
3
9
3


17596
00100010010111100
3
13
−3


18110
00100011010111110
3
9
1


19499
00100110000101011
3
13
−3


19578
00100110001111010
3
11
−1


19832
00100110101111000
3
11
−1


20590
00101000001101110
3
9
−3


20716
00101000011101100
3
13
−3


21054
00101001000111110
3
13
−1


21310
00101001100111110
3
9
1


22223
00101011011001111
3
9
3


22427
00101011110011011
3
13
3


23075
00101101000100011
3
13
−3


23480
00101101110111000
3
9
1


24749
00110000010101101
3
9
−3


24757
00110000010110101
3
11
−3


24765
00110000010111101
3
9
−1


25183
00110001001011111
3
9
1


25775
00110010010101111
3
9
1


25871
00110010100001111
3
9
−1


26578
00110011111010010
3
9
1


26743
00110100001110111
3
9
1


28180
00110111000010100
3
13
−3


30539
00111011101001011
3
13
3


31300
00111101001000100
3
13
−3


31946
00111110011001010
3
9
1


31958
00111110011010110
3
13
3


33229
01000000111001101
3
9
−3


34291
01000010111110011
3
9
1


35087
01000100100001111
3
11
−3


35151
01000100101001111
3
9
−1


35193
01000100101111001
3
9
−1


35301
01000100111100101
3
13
−1


37135
01001000100001111
3
13
−3


37150
01001000100011110
3
9
−3


37663
01001001100011111
3
11
1


38387
01001010111110011
3
9
3


38860
01001011111001100
3
9
1


38862
01001011111001110
3
11
3


39165
01001100011111101
3
9
3


41433
01010000111011001
3
9
−1


42183
01010010011000111
3
11
−1


42191
01010010011001111
3
13
1


42399
01010010110011111
3
9
3


42483
01010010111110011
3
11
3


42527
01010011000011111
3
9
1


42620
01010011001111100
3
9
1


45175
01011000001110111
3
9
1


45277
01011000011011101
3
13
1


45855
01011001100011111
3
13
3


45953
01011001110000001
3
9
−3


46105
01011010000011001
3
9
−3


46151
010110100001000111
3
13
−1


46199
01011010001110111
3
11
3


46704
01011011001110000
3
11
−1


46960
01011011101110000
3
9
1


48228
01011110001100100
3
11
−1


48921
01011111100011001
3
9
3


49885
01100001011011101
3
9
1


50366
01100010010111110
3
13
1


51445
01100100011110101
3
9
1


51719
01100101000000111
3
9
−3


51735
01100101000010111
3
9
−1


51743
01100101000011111
3
11
1


52600
01100110101111000
3
9
1


52741
01100111000000101
3
9
−3


53157
01100111110100101
3
9
3


53486
01101000011101110
3
13
1


54880
01101011001100000
3
9
−3


54908
01101011001111100
3
13
3


56801
01101110111100001
3
13
3


59009
01110011010000001
3
13
−3


59088
01110011011010000
3
11
−1


59346
01110011111010010
3
11
3


60436
01110110000010100
3
9
−3


60950
01110111000010110
3
13
1


61577
01111000010001001
3
13
−3


61714
01111000100010010
3
9
−3


63636
01111100010010100
3
13
−1


63892
01111100110010100
3
9
1


64070
01111101001000110
3
13
1


64196
01111110001100101
3
9
1


64613
01111110001100101
3
9
3


64817
01111110100110001
3
13
3


66254
10000001011001110
3
13
−3


66458
10000001110011010
3
9
−3


66875
10000010100111011
3
9
−1


67001
10000010110111001
3
13
−1


67179
10000011001101011
3
9
−1


67435
10000011101101011
3
13
1


69357
10000111011101101
3
9
3


69494
10000111101110110
3
13
3


70121
10001000111101001
3
13
−1


70635
10001001111101011
3
9
3


71725
10001100000101101
3
11
−3


71983
10001100100101111
3
11
1


72062
10001100101111110
3
13
3


74270
10010001000011110
3
13
−3


76163
10010100110000011
3
13
−3


76191
10010100110011111
3
9
3


77585
10010111100010001
3
13
−1


77914
10011000001011010
3
9
−3


78330
10011000111111010
3
9
3


78471
10011001010000111
3
9
−1


79328
10011010111100000
3
11
−1


79336
10011010111101000
3
9
1


79352
10011010111111000
3
9
3


79626
10011011100001010
3
9
−1


80705
10011101101000001
3
13
−1


81186
10011110100100010
3
9
−1


82150
10100000011100110
3
9
−3


82843
10100001110011011
3
11
1


84111
10100100010001111
3
9
−1


84367
10100100110001111
3
11
1


84872
10100101110001000
3
11
−3


84920
10100101110111000
3
13
1


84966
10100101111100110
3
9
3


85118
10100110001111110
3
9
3


85216
10100110011100000
3
13
−3


85794
10100111100100010
3
13
−1


85896
10100111110001000
3
9
−1


88451
10101100110000011
3
9
−1


88544
10101100111100000
3
9
−1


88588
10101101000001100
3
11
−3


88672
10101101001100000
3
9
−3


88880
10101101100110000
3
13
−1


88888
10101101100111000
3
11
1


89638
10101111000100110
3
9
1


91906
10110011100000010
3
9
−3


92209
10110100000110001
3
11
−3


92211
10110100000110011
3
9
−1


92684
10110101000001100
3
9
−3


93408
10110110011100000
3
11
−1


93921
10110111011100001
3
9
3


93936
10110111011110000
3
13
3


95770
10111011000011010
3
13
1


95878
10111011010000110
3
9
1


95920
10111011010110000
3
9
1


95984
10111011011110000
3
11
3


96780
10111101000001100
3
9
−1


97842
10111111000110010
3
9
3


99113
11000001100101001
3
13
−3


99125
11000001100110101
3
9
−1


99771
11000010110111011
3
13
3


100532
11000100010110100
3
13
−3


102891
11001000111101011
3
13
3


104328
11001011110001000
3
9
−1


104493
11001100000101101
3
9
−1


105200
11001101011110000
3
9
1


105296
11001101101010000
3
9
−1


105888
11001110110100000
3
9
−1


106306
11001111101000010
3
9
1


106314
11001111101001010
3
11
3


106322
11001111101010010
3
9
3


107591
11010010001000111
3
9
−1


107996
11010010111011100
3
13
3


108644
11010100001100100
3
13
−3


108848
11010100100110000
3
9
−3


109761
11010110011000001
3
9
−1


110017
11010110111000001
3
13
1


110355
11010111100010011
3
13
3


110481
11010111110010001
3
9
3


111239
11011001010000111
3
11
1


111493
11011001110000101
3
11
1


111572
11011001111010100
3
13
3


112961
11011100101000001
3
9
−1


113475
11011101101000011
3
13
3


114854
11100000010100110
3
9
−3


115353
11100001010011001
3
9
−1


115355
11100001010011011
3
11
1


115787
11100010001001011
3
9
−1


115802
11100010001011010
3
13
−1


116298
11100011001001010
3
11
−1


118184
11100110110101000
3
9
1


118950
11101000010100110
3
9
−1


119960
11101010010011000
3
9
−1


121882
11101110000011010
3
9
1


121900
11101110000101100
3
9
1


121946
11101110001011010
3
11
3


122032
11101110010110000
3
13
1


123154
11110000100010010
3
13
−3


123170
11110000100100010
3
11
−3


123212
11110000101001100
3
9
−1


123429
11110001000100101
3
9
−1


123685
11110001100100101
3
11
1


124194
11110010100100010
3
9
−1


124296
11110010110001000
3
13
−1


124490
11110011001001010
3
13
1


124628
11110011011010100
3
9
3


125233
11110100100110001
3
11
1


125516
11110101001001100
3
9
1


127142
11111000010100110
3
11
1


127178
11111000011001010
3
9
1


127378
11111000110010010
3
11
1


127386
11111000110011010
3
13
3


127785
11111001100101001
3
9
3


127818
11111001101001010
3
9
3


128140
11111010010001100
3
9
1
















TABLE 4







(n = 19)













max. corr.
max. corr.



number
bj
(forward)
(back)
dc level














3241
0000000110010101001
3
15
−7


10342
0000010100001100110
3
15
−7


26897
0000110100100010001
3
15
−7


28946
0000111000100010010
3
7
−7


33705
0001000001110101001
3
11
−5


34996
0001000100010110100
3
11
−7


37560
0001001001010111000
3
15
−5


59976
0001110101001001000
3
15
−5


61146
0001110111011011010
3
7
3


64429
0001111101110101101
3
9
5


66385
0010000001101010001
3
11
−7


70117
0010001000111100101
3
15
−3


74076
0010010000101011100
3
15
−5


86785
0010101001100000001
3
15
−7


92296
0010110100010001000
3
11
−7


95265
0010111010000100001
3
11
−5


97651
0010111110101110011
3
15
5


100875
0011000101000001011
3
15
−5


104970
0011001101000001010
3
15
−5


119844
0011101010000100100
3
15
−5


129885
0011111101101011101
3
11
7


130261
0011111110011010101
3
15
5


139806
0100010001000011110
3
11
−5


141571
0100010100100000011
3
11
−7


145426
0100011100000010010
3
15
−7


147682
0100100000011100010
3
15
−7


148592
0100100010001110000
3
7
−7


151815
0100101000100000111
3
9
−5


164556
0101000001011001100
3
15
−5


173571
0101010011000000011
3
15
−5


181179
0101100001110111011
3
15
3


187320
0101101101110111000
3
7
3


204961
0110010000010100001
3
15
−7


209056
0110011000010100000
3
15
−7


217591
0110101000111110111
3
11
5


218751
0110101011001111111
3
15
7


229006
0110111111010001110
3
15
5


232438
0111000101111110110
3
15
5


240123
0111010100111111011
3
11
7


244559
0111011101101001111
3
15
7


246306
0111100001000100010
3
11
−5


251865
0111101011111011001
3
15
7


253579
0111101111010001011
3
11
5


260523
0111111100110101011
3
15
7


263764
1000000011001010100
3
15
−7


270708
1000010000101110100
3
11
−5


272422
1000010100000100110
3
15
−7


277981
1000011110111011101
3
11
5


279728
1000100010010110000
3
15
−7


284164
1000101011000000100
3
11
−7


291849
1000111010000001001
3
15
−5


295281
1001000000101110001
3
15
−5


305536
1001010100110000000
3
15
−7


306696
1001010111000001000
3
11
−5


315231
1001100111101011111
3
15
7


319326
1001101111101011110
3
15
7


336967
1010010010001000111
3
7
−3


343108
1010011110001000100
3
15
−3


350716
1010101100111111100
3
15
5


359731
1010111110100110011
3
15
5


372472
1011010111011111000
3
9
5


375695
1011011101110001111
3
7
7


376605
1011011111100011101
3
15
7


378861
1011100011111101101
3
15
7


382716
1011101011011111100
3
11
7


384481
1011101110111100001
3
11
5


394026
1100000001100101010
3
15
−5


394402
1100000010010100010
3
11
−7


404443
1100010101111011011
3
15
5


419317
1100110010111110101
3
15
5


423412
1100111010111110100
3
15
5


426636
1101000001010001100
3
15
−5


429022
1101000101111011110
3
11
5


431991
1101001011101110111
3
11
7


437502
1101010110011111110
3
15
7


450211
1101101111010100011
3
15
5


454170
1101110111000011010
3
15
3


457902
1101111110010101110
3
11
7


459858
1110000010001010010
3
9
−5


463141
1110001000100100101
3
7
−3


464311
1110001010110110111
3
15
5


486727
1110110110101000111
3
15
5


489291
1110111011101001011
3
11
7


490582
1110111110001010110
3
11
5


495341
1111000111011101101
3
7
7


497390
1111001011011101110
3
15
7


513945
1111101011110011001
3
15
7


521046
1111111001101010110
3
15
7
















TABLE 5







(n = 21)













max. corr.
max. corr.
dc


number
bj
(forward)
(backward)
level














14773
000000011100110110101
3
15
−3


23865
000000101110100111001
3
13
−3


29546
000000111001101101010
3
11
−3


31157
000000111100110110101
3
11
−1


47731
000001011101001110011
3
15
−1


55754
000001101100111001010
3
11
−3


59029
000001110011010010101
3
11
−3


59093
000001110011011010101
3
15
−1


59245
000001110011101101101
3
15
1


60249
000001110101101011001
3
15
−1


62294
000001111001101010110
3
17
−1


81210
000010011110100111010
3
15
−1


89708
000010101111001101100
3
21
−1


183260
000101100101111011100
3
17
1


231861
000111000100110110101
3
15
−1


248388
000111100101001000100
3
13
−5


255570
000111110011001010010
3
13
−1


257750
000111110111011010110
3
13
5


276270
001000011011100101110
3
11
−1


281208
001000100101001111000
3
13
−5


281571
001000100101111100011
3
13
−1


331699
001010000111110110011
3
15
1


336446
001010010001000111110
3
13
−3


397237
001100000111110110101
3
15
1


406623
001100011010001011111
3
15
1


410091
001100100000111101011
3
15
−1


442901
001101100001000010101
3
13
−5


446288
001101100111101010000
3
21
−1


459446
001110000001010110110
3
11
−3


460219
001110000010110111011
3
13
1


490088
001110111101001101000
3
17
1


509010
001111100010001010010
3
13
−3


521034
001111111001101001010
3
17
3


521046
001111111001101010110
3
17
5


549238
010000110000101110110
3
17
−3


598815
010010010001100011111
3
15
−1


607356
010010100010001111100
3
13
−3


609528
010010100110011111000
3
13
−1


614638
010010110000011101110
3
13
−1


659673
010100001000011011001
3
15
−5


672243
010100100000111110011
3
15
−1


674879
010100100110000111111
3
11
1


674943
010100100110001111111
3
15
3


675271
010100100110111000111
3
15
1


678396
010100101100111111100
3
17
3


684896
010100111001101100000
3
11
−3


693023
010101001001100011111
3
15
1


709407
010101101001100011111
3
11
3


711104
010101101100111000000
3
11
−3


718739
010101111011110010011
3
13
5


759696
010111001011110010000
3
15
−1


783558
010111111010011000110
3
21
3


812538
011000110010111111010
3
21
3


813247
011000110100010111111
3
13
3


827125
011001001111011110101
3
15
5


828703
011001010010100011111
3
15
1


846657
011001110101101000001
3
15
−1


874976
011010101100111100000
3
17
−1


875004
011010101100111111100
3
17
5


880376
011010110111011111000
3
13
5


895004
011011010100000011100
3
11
−3


896785
011011010111100010001
3
13
1


905410
011011101000011000010
3
17
−3


957828
011101001110110000100
3
11
−1


975058
011101110000011010010
3
13
−1


975177
011101110000101001001
3
13
−1


1018004
011111000100010010100
3
13
−3


1025305
011111010010100011001
3
15
1


1071846
100000101101011100110
3
15
−1


1079147
100000111011101101011
3
13
3


1121974
100010001111010110110
3
13
1


1122093
100010001111100101101
3
13
1


1139323
100010110001001111011
3
11
1


1191741
100100010111100111101
3
17
3


1200366
100100101000011101110
3
13
−1


1202147
100100101011111100011
3
11
3


1216775
100101001000100000111
3
13
−5


1222147
100101010011000000011
3
17
−5


1222175
100101010011000011111
3
17
1


1250494
100110001010010111110
3
15
1


1268448
100110101101011100000
3
15
−1


1270026
100110110000100001010
3
15
−5


1283904
100111001011101000000
3
13
−3


1284613
100111001101000000101
3
21
−3


1313593
101000000101100111001
3
21
−3


1337455
101000110100001101111
3
15
1


1378412
101010000100001101100
3
13
−5


1386047
101010010011000111111
3
11
3


1387744
101010010110011100000
3
11
−3


1404128
101010110110011100000
3
15
−1


1412255
101011000110010011111
3
11
3


1418755
101011010011000000011
3
17
−3


1421880
101011011001000111000
3
15
−1


1422208
101011011001110000000
3
15
−3


1422272
101011011001111000000
3
11
−1


1424908
101011011111000001100
3
15
1


1437478
101011110111100100110
3
15
5


1482513
101101001111100010001
3
13
1


1487623
101101011001100000111
3
13
1


1489795
101101011101110000011
3
13
3


1498336
101101101110011100000
3
15
1


1547913
101111001111010001001
3
17
3


1576105
110000000110010101001
3
17
−5


1576117
110000000110010110101
3
17
3


1588141
110000011101110101101
3
13
3


1607063
110001000010110010111
3
17
−1


1636932
110001111101001000100
3
13
−1


1637705
110001111110101001001
3
11
3


1650863
110010011000010101111
3
21
1


1654250
110010011110111101010
3
13
5


1687060
110011011111000010100
3
15
1


1690528
110011100101110100000
3
15
−1


1699914
110011111000001001010
3
15
−1


1760705
110101101110111000001
3
13
3


1765452
110101111000001001100
3
15
−1


1815580
110111011010000011100
3
13
1


1815943
110111011010110000111
3
13
5


1820881
110111100100011010001
3
11
1


1839401
111000001000100101001
3
13
−5


1841581
111000001100110101101
3
13
1


1848763
111000011010110111011
3
13
5


1865290
111000111011001001010
3
15
1


1913891
111010011010000100011
3
17
−1


2007443
111101010000110010011
3
21
1


2015941
111101100001011000101
3
15
1


2034857
111110000110010101001
3
17
1


2036902
111110001010010100110
3
15
1


2037906
111110001100010010010
3
15
−1


2038058
111110001100100101010
3
15
1


2038122
111110001100101101010
3
11
3


2041397
111110010011000110101
3
11
3


2049420
111110100010110001100
3
15
1


2065994
111111000011001001010
3
11
1


2067605
111111000110010010101
3
11
3


2073286
111111010001011000110
3
13
3


2082378
111111100011001001010
3
15
3
















TABLE 6







(n = 23)














max.






corr.





max. corr.
(back-
dc


number
bj
(forward)
ward)
level














29362
00000000111001010110010
3
15
−7


75541
00000010010011100010101
3
11
−7


86422
00000010101000110010110
3
15
−7


115861
00000011100010010010101
3
11
−7


271825
00001000010010111010001
3
11
−7


272197
00001000010011101000101
3
15
−7


333508
00001010001011011000100
3
11
−7


345892
00001010100011100100100
3
15
−7


463141
00001110001000100100101
3
11
−7


476197
00001110100010000100101
3
11
−7


496708
00001111001010001000100
3
15
−7


543651
00010000100101110100011
3
11
−5


789930
00011000000110110101010
3
15
−5


1031085
00011111011101110101101
3
11
7


1082833
00100001000010111010001
3
11
−7


1083205
00100001000011101000101
3
11
−7


1116052
00100010000011110010100
3
11
−7


1119472
00100010001010011110000
3
15
−7


1142932
00100010111000010010100
3
11
−7


1160272
00100011011010001010000
3
11
−7


1181041
00100100000010101110001
3
15
−7


1208656
00100100111000101010000
3
15
−7


1345348
00101001000011101000100
3
11
−7


1372228
00101001111000001000100
3
11
−7


1524769
00101110100010000100001
3
11
−7


1906423
00111010001011011110111
3
11
5


1994730
00111100110111111101010
3
15
7


2285833
01000101110000100001001
3
11
−7


2429191
01001010001000100000111
3
11
−7


2533120
01001101010011100000000
3
15
−7


2807832
01010101101100000011000
3
15
−5


2846271
01010110110111000111111
3
11
7


2854335
01010111000110110111111
3
11
7


2882364
01010111111101100111100
3
15
7


2965230
01011010011111011101110
3
15
7


2997135
01011011011101110001111
3
11
7


3010191
01011011110111010001111
3
11
7


3050991
01011101000110111101111
3
15
7


3051387
01011101000111101111011
3
11
7


3128430
01011111011110001101110
3
11
7


3141006
01011111110110110001110
3
15
7


3458368
01101001100010101000000
3
15
−7


3652701
01101111011110001011101
3
11
7


3715035
01110001010111111011011
3
15
7


3726330
01110001101101111111010
3
15
7


3812847
0111010001011011110111
3
11
7


3813243
01110100010111101111011
3
11
7


3874554
01110110001111011111010
3
11
7


3910974
01110111010110100111110
3
11
7


3915354
01110111011111001011010
3
15
7


3922494
01110111101101000111110
3
11
7


4058763
01111011110111010001011
3
11
7


4074990
01111100010110111101110
3
11
7


4086510
01111100101101011101110
3
11
7


4302097
10000011010010100010001
3
11
−7


4313617
10000011101001000010001
3
11
−7


4329844
10000100001000101110100
3
11
−7


4466113
10001000010010111000001
3
11
−7


4473253
10001000100000110100101
3
15
−7


4477633
10001000101001011000001
3
11
−7


4514053
10001001110000100000101
3
11
−7


4575364
1000101110100001000010
3
11
−7


4575760
10001011101001000010000
3
11
−7


4662277
10001110010010000000101
3
15
−7


4673572
10001110101000000100100
3
15
−7


4735906
10010000100001110100010
3
11
−7


4930239
10010110011101010111111
3
15
7


5247601
10100000001001001110001
3
15
−7


5260177
10100000100001110010001
3
11
−7


5337220
10100010111000010000100
3
11
−7


5337616
10100010111001000010000
3
15
−7


5378416
10100100001000101110000
3
11
−7


5391472
10100100100010001110000
3
11
−7


5423377
10100101100000100010001
3
15
−7


5506243
10101000000010011000011
3
15
−7


5534272
1010100011100100100000
3
11
−7


5542336
1010100100100011100000
3
11
−7


5580775
10101010010011111100111
3
15
5


5855487
10110010101100011111111
3
15
7


5959416
10110101110111011111000
3
11
7


6102774
10111010001111011110110
3
11
7


6393877
11000011001000000010101
3
15
−7


6482184
11000101110100100001000
3
11
−5


6863838
11010001011101111011110
3
11
7


7016379
11010110000111110111011
3
11
7


7043259
11010110111100010111011
3
11
7


7179951
11011011000111010101111
3
15
7


7207566
11011011111101010001110
3
15
7


7228335
11011100100101110101111
3
11
7


7245675
11011101000111101101011
3
11
7


7269135
11011101110101100001111
3
15
7


7272555
11011101111100001101011
3
11
7


7305402
11011110111100010111010
3
11
7


7305774
11011110111101000101110
3
11
7


7357522
11100000100010001010010
3
11
−7


7598677
11100111111001001010101
3
15
5


7844956
11101111011010001011100
3
11
5


7891899
11110000110101110111011
3
15
7


7912410
11110001011101111011010
3
11
7


7925466
11110001110111011011010
3
11
7


8042715
11110101011100011011011
3
15
7


8055099
11110101110100100111011
3
11
7


8116410
11110111101100010111010
3
15
7


8116782
11110111101101000101110
3
11
7


8272746
11111100011101101101010
3
11
7


8302185
11111101010111001101001
3
15
7


8313066
11111101101100011101010
3
11
7


8359245
11111111000110101001101
3
15
7
















TABLE 7







(n = 25)














max.






corr.





max. corr.
(back-
dc


number
bj
(forward)
ward)
level














381638
0000001011101001011000110
3
11
−5


446005
0000001101100111000110101
3
13
−3


465770
0000001110001101101101010
3
13
−3


473782
000000111001110101011010
3
13
−1


897941
0000011011011001110010101
3
13
−1


947565
0000011100111010101101101
3
15
1


2054758
000011111010110100110010
3
13
1


2054886
0000111110101101011100110
3
11
3


3275446
000110001111110101011010
3
17
3


3672501
0001110000000100110110101
3
15
−5


3672793
0001110000000101011011001
3
13
−5


4808590
0010010010101111110001110
3
15
1


4945678
0010010110111011100001110
3
13
1


6550893
0011000111111010101101101
3
13
5


6561626
0011001000001111101011010
3
11
−1


6692698
0011001100001111101011010
3
13
1


7093738
0011011000011110111101010
3
11
3


7345002
0011100000001001101101010
3
13
−5


7345586
0011100000001010101101010
3
17
−5


9609331
0100100101010000001110011
3
13
−5


9610015
0100100101010001100011111
3
15
−1


10178588
0100110110101000000011100
3
17
−5


10805191
0101001001101111111000111
3
15
5


10950975
0101001110001100100111111
3
13
3


11297951
0101011000110010010011111
3
13
1


11374620
0101011011001000000011100
3
13
−5


11383232
0101011011011000111000000
3
13
−3


11499628
0101011110111100001101100
3
11
3


11923532
0101101011111000001001100
3
11
−1


11923660
0101101011111000011001100
3
13
1


13014848
0110001101001011101000000
3
11
−5


13197255
0110010010101111111000111
3
13
5


13415920
0110011001011010111110000
3
13
1


13546992
0110011101011010111110000
3
11
3


14334400
0110110101011100111000000
3
13
−1


14335768
0110110101011111100011000
3
17
3


14802340
0111000011101110110100100
3
13
1


14939428
0111000111111010100100100
3
15
1


18615003
1000111000000101011011011
3
15
−1


18752091
1000111100010001001011011
3
13
−1


19218663
1001001010100000011100111
3
17
−3


19220031
1001001010100011000111111
3
13
1


20007439
1001100010100101000001111
3
11
−3


2013851
1001100110100101000001111
3
13
−1


20357176
1001101101010000000111000
3
13
−5


20539583
1001110010110100010111111
3
11
5


21630771
1010010100000111100110011
3
13
−1


21630899
1010010100000111110110011
3
11
1


22054803
1010100001000011110010011
3
11
−3


22171199
1010100100100111000111111
3
13
3


22179811
1010100100110111111100011
3
13
5


22256480
1010100111001101101100000
3
13
−1


22603456
1010110001110011011000000
3
13
−3


22749240
1010110110010000000111000
3
15
−5


23375843
1011001001010111111100011
3
17
5


23944416
1011011010101110011100000
3
15
1


23945100
1011011010101111110001100
3
13
5


26208845
1100011111110101001001101
3
17
5


26209429
1100011111110110010010101
3
13
5


26460693
1100100111100001000010101
3
11
−3


26861733
1100110011110000010100101
3
13
−1


26992805
1100110111110000010100101
3
11
1


27003538
1100111000000101010010010
3
13
−5


28608753
1101101001000100011110001
3
13
−1


28745841
110110110101000001110001
3
15
−1


29881638
1110001111111010100100110
3
13
5


29881930
1110001111111011001001010
3
15
5


30278985
1110011100000010101001001
3
17
−3


31499545
1111000001010010100011001
3
11
−3


31499673
1111000001010010110011001
3
13
−1


32606866
1111100011000101010010010
3
15
−1


32656490
1111100100100110001101010
3
13
1


33080649
1111110001100010101001001
3
13
1


33088661
1111110001110010010010101
3
13
3


33108426
1111110010011000111001010
3
13
3


33172793
1111110100010110100111001
3
11
5
















TABLE 8







(n = 27)













max.
max.





corr.
corr.





(for-
(back-
dc 


number
bj
ward)
ward)
level














930410
000000011100011001001101010
3
15
−7


1624362
000000110001100100100101010
3
15
−9


1860757
000000111000110010010010101
3
15
−7


15798573
000111100010001000100101101
3
11
−5


39566215
010010110111011101110000111
3
11
5


44341440
010101001001001100011000000
3
15
−9


45245312
010101100100110001110000000
3
15
−7


45534783
010101101101100111000111111
3
15
7
















TABLE 9







(n = 29)













max. corr.
max.



number
bj
(forward)
corr. (backward)
dc level














11687143
00000101100100101010011100111
3
15
−3


20815162
00001001111011001110100111010
3
15
1


29650650
00001110001000110111011011010
3
17
−1


52082271
00011000110101011011001011111
3
15
3


52401586
00011000111111100101011011010
3
15
1


52417970
00011000011111101010110110010
3
11
3


69590574
00100001001011101111000101110
3
13
1


70752046
00100001101111001011100101110
3
19
1


79132430
00100101101110111011100001110
3
15
3


162536693
01001101100000001110011110101
3
15
−1


162873112
01001101101010011111100011000
3
15
1


162889496
01001101101010111111100011000
3
11
3


169410125
01010000110001111111001001101
3
15
1


191808624
01011011011101100010001110000
3
17
−1


194459536
01011100101110011011110010000
3
15
1


236838308
01110000111011101110110100100
3
15
3


244282500
01110100011110111010010000100
3
19
−1


245185924
01110100111010011110110000100
3
19
1












BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a system block diagram of a spread spectrum communication device showing a first application example of the present invention;
FIG. 2 is a diagram illustrating a signal code sequence;
FIG. 3 is a system block diagram of a part of a communication device showing a second application example of the present invention;
FIG. 4 shows a surface acoustic wave device using a second application example of the present invention;
FIG. 5 is a system block diagram of a spread spectrum communication device showing a third application example of the present invention;
FIG. 6 shows a code sequence used in the third application example of the present invention;
FIG. 7 shows a matched signal used in the third application example of the present invention;
FIG. 8 shows the frequency response of a matched filter used in the third application example of the present invention;
FIG. 9 shows a conventional Barker code (13 chips);
FIG. 10 shows a matched signal in the case where the conventional Barker code (13 chips) is used;
FIG. 11 shows the frequency response of a matched filter in the case where the conventional Barker code (13 chips) is used;
FIG. 12 shows tap coefficients of a matched filter using a fourth application example of the present invention;
FIG. 13 shows a matched signal used in the fourth application example of the present invention;
FIG. 14 shows tap coefficients of a matched filter using a fifth application example of the present invention;
FIG. 15 shows a matched signal used in the fifth application example of the present invention;
FIG. 16 is a system block diagram of a spread spectrum communication device showing a sixth application example of the present invention;
FIG. 17 is a system block diagram of a part of a communication device showing a seventh application example of the present invention;
FIG. 18 is a system block diagram of a part of a communication device showing an eighth application example of the present invention;
FIG. 19 is a system block diagram of a part of a communication device showing a ninth application example of the present invention;
FIG. 20 is a system block diagram of a part of a communication device showing a tenth application example of the present invention;
FIG. 21 is a system block diagram of a part of a communication device showing an eleventh application example of the present invention; and
FIG. 22 shows a communication system using a device shown in a twelfth application example of the present invention.



BEST MODE FOR CARRYING OUT THE INVENTION
Hereafter, modes for carrying out the present invention will be described by referring to FIGS. 1 through 23.
However, some modes hereafter described are shown in order to explain application examples for carrying out the present invention. Modes for carrying out the present invention are never limited to application examples described here.
FIG. 1 is a diagram schematically showing a spread spectrum communication device to which the present invention has been applied. An information signal is inputted from an input terminal 1, multiplied in a mixer 2 by a signal supplied from a pseudo noise code generator 3, furthermore multiplied in a mixer 4 by a carrier supplied from an oscillator 5, amplified in an amplifier 6, and outputted from an antenna 7. Here, a code shown in TABLES 1 through 9 was used as the pseudo noise code.
In a receiving system, a signal inputted from the antenna 7 is amplified in an amplifier 8, demodulated, converted to a digital signal in a square wave output circuit 9, and taken out from an output terminal 10 as an information signal. Here, a code similar to the above described code was used as a reference code for demodulating the information. (It coincides with the pseudo noise code of the transmitter.) FIG. 2 is a diagram showing a signal code sequence. In the case of the synchronous detection system, a signal code sequence Sk corresponds to 1 and 0 of the information code, and it is represented as




  
    
      
        
          S
          k
        
        =
        
          [
          
            
              
                
                  
                    m
                    
                      mod
                      ⁢
                      
                        
                      
                      ⁢
                      
                        (
                        
                          k
                          /
                          n
                        
                        )
                      
                    
                  
                  ⁡
                  
                    (
                    
                      data
                      =
                      
                        1
                        ⁢
                        
                          
                        
                        ⁢
                        or
                        ⁢
                        
                          
                        
                        ⁢
                        0
                      
                    
                    )
                  
                
              
            
            
              
                
                  -
                  
                    
                      m
                      
                        mod
                        ⁢
                        
                          
                        
                        ⁢
                        
                          (
                          
                            k
                            /
                            n
                          
                          )
                        
                      
                    
                    ⁡
                    
                      (
                      
                        data
                        =
                        
                          0
                          ⁢
                          
                            
                          
                          ⁢
                          or
                          ⁢
                          
                            
                          
                          ⁢
                          1
                        
                      
                      )
                    
                  
                
              
            
          
        
      
    
    
      
        (
        
          Expression
          ⁢
          
            
          
          ⁢
          1
        
        )
      
    
  




where mj (j=1, 2, . . . , n; n=code length) corresponds to a pseudo noise code bj shown in TABLES 1 through 9, and it is represented by the following equation.





  
    
      
        
          m
          j
        
        =
        
          [
          
            
              
                
                  1
                  ⁢
                  
                    
                  
                  ⁢
                  
                    (
                    
                      
                        b
                        j
                      
                      =
                      1
                    
                    )
                  
                
              
            
            
              
                
                  
                    -
                    1
                  
                  ⁢
                  
                    
                  
                  ⁢
                  
                    (
                    
                      
                        b
                        j
                      
                      =
                      0
                    
                    )
                  
                
              
            
          
        
      
    
    
      
        (
        
          Expression
          ⁢
          
            
          
          ⁢
          2
        
        )
      
    
  




In the same way, in the case of the delay detection system, the signal code sequence Sk is represented by the following equation.





  
    
      
        
          S
          k
        
        =
        
          [
          
            
              
                
                  
                    m
                    
                      mod
                      ⁢
                      
                        
                      
                      ⁢
                      
                        (
                        
                          k
                          /
                          n
                        
                        )
                      
                    
                  
                  ⁢
                  
                    
                      S
                      
                        k
                        -
                        1
                      
                    
                    ⁡
                    
                      (
                      
                        data
                        =
                        
                          1
                          ⁢
                          
                            
                          
                          ⁢
                          or
                          ⁢
                          
                            
                          
                          ⁢
                          0
                        
                      
                      )
                    
                  
                
              
            
            
              
                
                  
                    -
                    
                      m
                      
                        mod
                        ⁢
                        
                          
                        
                        ⁢
                        
                          (
                          
                            k
                            /
                            n
                          
                          )
                        
                      
                    
                  
                  ⁢
                  
                    
                      S
                      
                        k
                        -
                        1
                      
                    
                    ⁡
                    
                      (
                      
                        data
                        =
                        
                          0
                          ⁢
                          
                            
                          
                          ⁢
                          or
                          ⁢
                          
                            
                          
                          ⁢
                          1
                        
                      
                      )
                    
                  
                
              
            
          
        
      
    
    
      
        (
        
          Expression
          ⁢
          
            
          
          ⁢
          3
        
        )
      
    
  




Denoting a reference code of the receiving side by Mj, a correlation coefficient Ok is represented by the following equation.





  
    
      
        
          O
          k
        
        =
        
          
            ∑
            
              j
              =
              1
            
            n
          
          ⁢
          
            
              S
              
                k
                +
                j
                -
                1
              
            
            ⁢
            
              M
              j
            
          
        
      
    
    
      
        (
        
          Expression
          ⁢
          
            
          
          ⁢
          4
        
        )
      
    
  




In the case where Mj=mj, the correlation coefficient Ok represents an auto-correlation coefficient and it is represented by the following equation.





  
    
      
        
          O
          k
        
        =
        
          
            ∑
            
              j
              =
              1
            
            n
          
          ⁢
          
            
              S
              
                k
                +
                j
                -
                1
              
            
            ⁢
            
              m
              j
            
          
        
      
    
    
      
        (
        
          Expression
          ⁢
          
            
          
          ⁢
          5
        
        )
      
    
  




Sub-peaks other than correlation peaks (mod(k/n)=1) are referred to as side lobes. As this value becomes smaller, the error rate of the receiver is typically reduced. For the case where the code length is at least 14, such a code that the side lobe value calculated by using the Expression 5 is 3 or less is shown in TABLES 1 through 9. Calculation conducted here corresponds to all arrangements (0, 0), (0, 1), (1, 0) and (1, 1) of 0 and 1 of the information code. (The above described 0 and 1 of the information code indicate that they are mutually in the relation of inverted code.) Calculation was conducted as to such an arrangement of Sk that signs whereby mj is multiplied are (+, +, −). That is, calculating to Expression 5 above is performed o a single code sequence Sk which includes Mjs have signs (+,+,−), respectively (i.e., Sk=+Mj,+Mj−Mj). (In the remaining case where the signs are (−, −, +), a result equal in absolute value and opposite in sign to the above described result is obtained. In other words, only the polarity is different. Therefore, the above described calculation alone suffices.)

In TABLES 1 through 9, “bj” is a derived code sequence, and “number” is a value obtained by regarding the “bj” as a binary number and converting it to a decimal number. Furthermore, “max corr. (forward)” is a side lobe value, and “max corr. (backward)” is a maximum value of correlation value obtained in the case where codes are reversed bilaterally. Furthermore, “dc level” is the sum total of n “mj”s. As a matter of course, similar results are obtained even if code inversion (10) is conducted on these codes. Since it takes an enormous time to conduct calculations, inverted codes are omitted for lengthy code lengths. If these codes are used as the pseudo noise code, there is obtained a spread spectrum communication device having a processing gain of at least 14 in auto-correlation side lobe, having smaller time-axis side lobes of received matched signal, having a smaller error rate, and having favorable characteristics.
A second application example of the present invention will now be described by referring to FIG. 3. The same components as those in FIG. 1 showing the first application example are denoted by like numerals. FIG. 3 is a diagram showing a receiving part of the second application example of the present invention. A received signal taken in from an antenna 7 is amplified in an amplifier 8, converted to a matched signal in a matched filter 11, detected in a detector circuit 12, demodulated, converted to a digital signal by a square wave output circuit 13, and outputted from an output terminal 10. In the present application example, a matched filter is used as a demodulating element. This results in a feature that the circuit can be simply formed.
A third application example of the present invention will now be described by referring to FIGS. 4 and 5.
FIG. 4 is a diagram schematically showing a SAW (surface acoustic wave) matched filter 18. On a SAW substrate 14, an input interdigital electrode set 15 and an output interdigital electrode set 16 are disposed. Furthermore, in order to suppress a reflected wave coming from a substrate face, a sound absorbing material 17 is coated. The input interdigital electrode set 15 has such a structure that the electrode polarity is inverted every electrode. (The electric polarity differs depending upon whether the electrode is connected to an upper common electrode or a lower common electrode.) The output interdigital electrode set 16 has a matched filter structure in which the electrode polarity is inverted in association with the pseudo noise code. As the substrate 14, an ST-cut crystal substrate is used in order to prevent the center frequency from being shifted due to the temperature.
FIG. 5 is a system block diagram of the present application example. The same components as those in FIG. 1 showing the first application example are denoted by like numerals. A received signal taken in from an antenna 7 is amplified in an amplifier 8, converted to a matched signal in a SAW matched filter 18 of the present application example, multiplied in a mixer 20 by a signal preceding it by one information bit and delayed in a SAW delay line 19 and thus detected, converted in a square wave output circuit 13 to a digital signal, and outputted from an output terminal 10. In the present application example, delay detection is conducted by using an SAW element. This results in a feature that the detector circuit can be formed more simply.
FIG. 6 is a diagram showing mj corresponding to a 25-chip code bj of number (num) 947565 shown in TABLE 7.
FIG. 7 is a diagram showing a matched signal waveform in the case where this mj code is used on the transmitting side and the reference code of the matched filter on the receiving side is made the same. The carrier frequency is 300 MHz, and the information rate is 1 Mbps. At this time, a favorable side lobe suppression factor (peak to side lobe ratio D/U=18.2 dB) is obtained.
FIG. 8 is a diagram showing the frequency response of the matched filter of the present application example. In FIG. 8, ripples on the frequency response correspond to side lobe deterioration. For the purpose of comparison, the case where the conventional 13-chip Barker code is used will now be also described.
FIG. 9 is a diagram showing mj corresponding to this Barker code.
FIG. 10 is a diagram showing the matched signal waveform in the case where this mj code is used on the transmitting side and the reference code of the matched filter on the receiving side is made the same.
In the same way as the present application example, the carrier frequency was set equal to 300 MHz and the information rate was set equal to 1 Mbps. A side lobe suppression factor (peak to side lobe ratio D/U=22.1 dB) was obtained.
FIG. 11 is a diagram showing the frequency response of the matched filter in the case where the Barker code is used. It is shown that ripples are comparatively small and the side lobe suppression factor is large.
As described above, use of the present application example makes it possible to obtain a communication device having a chip length of 25 and improve significantly the processing gain at the sacrifice of only a slight side lobe deterioration as compared with the case where the conventional Barker code is used.
A fourth application example of the present invention will now be described by referring to FIGS. 12 and 13. In the above described third application example, the side lobe suppression factor was D/U=18.2 dB. In the present application example, however, further side lobe suppression is conducted.
FIG. 12 is a diagram showing a reference 25-chip tap coefficient Mj of the receiving side in the present application example. In order to conduct side lobe suppression of the matched signal, respective taps are provided with weights.
FIG. 13 shows a matched signal waveform in the case where the mj code of the third application example are used on the transmitting side and respective taps of the matched filter of the receiving side are provided with weights corresponding to the above described reference code NJ. Coefficients of FIG. 12 were derived by using an optimization algorithm. The carrier frequency is 300 MHz, and the information rate is 1 Mbps. By doing so, a favorable side lobe suppression factor (peak to side lobe ratio D/U=19.8 dB) as compared with the third application example is obtained without increasing the number of taps of the receiving side.
A fifth application example of the present invention will now be described by referring to FIGS. 14 and 15. In the fourth application example, the number of taps was set equal to 25 equally for both the transmitting side and the receiving side. In the present application example, however, the number of taps on the receiving side was set equal to 49 in order to conduct further side lobe suppression.
FIG. 14 is a diagram showing the reference 49-chip tap coefficient NJ on the receiving side of the present application example. For matched signal side lobe suppression, respective taps are provided with weights.
FIG. 15 is a diagram showing a matched signal waveform in the case where the mj code of the third application example is used on the transmitting side and respective taps of the matched filter on the receiving side are provided with weights corresponding to the above described reference code MJ. Coefficients of FIG. 14 were derived by using the optimization algorithm. The carrier frequency is 300 MHz, and the information rate is 1 Mbps. As compared with the conventional case where the Barker code is used, a favorable side lobe suppression factor (peak to side lobe ratio D/tJ=24.4 dB) is obtained.
A sixth application example of the present invention will now be described by referring to FIG. 16. The same components as those in FIG. 5 showing the third application example are denoted by like numerals. In the third application example, demodulation is conducted directly in the transmission signal band. Since the frequency is high, however, signal processing is difficult in some cases. In the present application example, the frequency is lowered by multiplying the received signal with a signal generated by an oscillator 22 conducted in a mixer 21 and thereafter demodulation processing is conducted. If the present application example is used, demodulation processing with a comparatively low frequency band is possible, resulting in a feature of easy circuit design.
A seventh application example of the present invention will now be described by referring to FIG. 17.
FIG. 17 is a diagram showing a receiving part of a communication device in the seventh application example. The same components as those in FIG. 3 showing the second application example are denoted by like numerals. In the second application example, demodulation is conducted by using a matched filter. In the case where the information rate is slow, however, the device size of the matched filter becomes large. In the present application example, an signal outputted from a pseudo noise code generator 23 is multiplied in a mixer 24 by a carrier signal of an oscillator 25 having the same frequency as that of the carrier, and a resultant signal is synchronized with the received signal and it is multiplied in a mixer 26 by the received signal. As a result, a demodulated signal can be obtained. The present application example has a feature that signal demodulation can be conducted without increasing the device size even in the case where the information rate is comparatively slow.
An eighth application example of the present invention will now be described by referring to FIG. 18.
FIG. 18 is a diagram showing a receiving part of a communication device in the eighth application example. The same components as those in FIG. 3 showing the second application example are denoted by like numerals. In the seventh application example, a pseudo noise signal is generated to conduct demodulation. On the receiver side as well, however, a signal generator is needed, resulting in a large circuit scale. In the present application example, a carrier frequency oscillator 28 is multiplied in a mixer 27 by the received signal. Furthermore, a resultant signal is converted to a digital signal by a detector circuit 29 and a square wave output circuit 30. In a digital correlation signal processing circuit 31, the digital signal is subjected to processing according to the equation of the Expression 4 and the equation of the Expression 5. In the present application example, correlation demodulation processing can be conducted by using digital processing. This results in a feature that the device can be fabricated at comparatively low cost in the case where the information rate is comparatively slow, or the pseudo noise code length is short.
A ninth application example of the present invention will now be described by referring to FIG. 19.
FIG. 19 is a diagram showing a receiving part of a communication device in the ninth application example. The same components as those in FIG. 17 showing the seventh application example are denoted by like numerals. In the eighth application example, demodulation is conducted in the digital circuit. In the case where the information rate is fast and the pseudo noise code length is long, processing cannot be conducted in some oases because the clock frequency of the digital circuit is low. In the present application example, a signal outputted from a pseudo noise code generator 23 is multiplied in a mixer 24 by a carrier signal of an oscillator 25 having the same frequency as the carrier. A resultant signal and the received signal are subjected to convolution integral processing in a convolver 32 which is a correlation element. Furthermore, a resultant signal is subjected to demodulation in a detector circuit 33. The present application example has a feature that the demodulated signal can be obtained comparatively easily so long as the carrier frequency can be synchronized with the pseudo noise code cycle even in the case where the information rate is fast and the pseudo noise code length is long.
As compared with the sixth through ninth application examples, the case where the matched filter is used as in the second and third application examples has a feature that signal synchronizing is unnecessary because the code on the receiving side is fixed. On the contrary, the sixth through ninth application examples have a feature that the reference code on the receiving side can be changed freely so as to correspond to the code on the transmitting side because the code is variable.
A tenth application example of the present invention will now be described by referring to FIG. 20.
FIG. 20 is a diagram showing a detection part of a communication device in the tenth application example. In the present application example, a delay detection system is used as the detection system, and demodulation is conducted by multiplying a current signal, in a mixer 35, by a signal preceding a current signal by one information bit supplied from a delay line 34. In the present application example, the detector circuit can be simplified.
An eleventh application example of the present invention will now be described by referring to FIG. 21.
FIG. 21 is a diagram showing a detection part of a communication device of the eleventh application example. In the present application example, a synchronous detection system is used as the detection system, and demodulation is conducted by multiplying a clock reproduced by a clock detection circuit 36, in a mixer 35, by a signal. In the present application example, a better error rate than that of the delay detection system is obtained.
A twelfth application example of the present invention will be now described by referring to FIG. 22.
FIG. 22 is a diagram showing a communication system of the twelfth application example. In the present application example, communication devices of the present system are used in a LAN. Present communication devices 41 and 42 are connected to a LAN cable 38. Present communication devices 40 and 43 are connected to terminals 39 and 44. Present communication devices 46 and 47 are connected to terminals 45 and 48. Between terminals (without a wire system between), communication can be conducted freely. If the present application example is used, it is not necessary to connect each terminal to a LAN cable, and consequently terminals can be freely moved.
INDUSTRIAL APPLICABILITY
According to the present invention, the side lobes of the correlation coefficient can be suppressed with the pseudo noise code length of at least 14 as heretofore described. Therefore, the error rate can be reduced and the processing gain can be improved in a spread spectrum communication device and a communication system using the spread spectrum communication device.

## Claims

1. A spread spectrum communication receiver comprising: a receiver which receives a signal using a pseudo noise code from a transmitter; and
a matched filter which has taps, each tap having a weight,
wherein said transmitter has a pseudo noise code generator for generating, as said pseudo noise code, a code sequence having a code length of at least 14 and having a value corresponding to a peak of one of plural absolute auto-correlation side lobes having a smallest value, which is calculated such that in a synchronous detection system, a signal code sequence Sk corresponds to 1 and 0 of an information signal and is represented by the following equation:





  
    
      
        
          S
          k
        
        =
        
          [
          
            
              
                
                  
                    m
                    
                      mod
                      ⁢
                      
                        
                      
                      ⁢
                      
                        (
                        
                          k
                          /
                          n
                        
                        )
                      
                    
                  
                  ⁡
                  
                    (
                    
                      data
                      =
                      
                        1
                        ⁢
                        
                          
                        
                        ⁢
                        or
                        ⁢
                        
                          
                        
                        ⁢
                        0
                      
                    
                    )
                  
                
              
            
            
              
                
                  -
                  
                    
                      m
                      
                        mod
                        ⁢
                        
                          
                        
                        ⁢
                        
                          (
                          
                            k
                            /
                            n
                          
                          )
                        
                      
                    
                    ⁡
                    
                      (
                      
                        data
                        =
                        
                          0
                          ⁢
                          
                            
                          
                          ⁢
                          or
                          ⁢
                          
                            
                          
                          ⁢
                          1
                        
                      
                      )
                    
                  
                
              
            
          
        
      
    
    
      
        (
        
          Expression
          ⁢
          
            
          
          ⁢
          1
        
        )
      
    
  



wherein mj (j=1, 2, . . . , n; n=code length) corresponds to one of the pseudo noise codes bj as represented by the following equation:





  
    
      
        
          m
          j
        
        =
        
          [
          
            
              
                
                  1
                  ⁢
                  
                    
                  
                  ⁢
                  
                    (
                    
                      
                        b
                        j
                      
                      =
                      1
                    
                    )
                  
                
              
            
            
              
                
                  
                    -
                    1
                  
                  ⁢
                  
                    
                  
                  ⁢
                  
                    (
                    
                      
                        b
                        j
                      
                      =
                      0
                    
                    )
                  
                
              
            
          
        
      
    
    
      
        (
        
          Expression
          ⁢
          
            
          
          ⁢
          2
        
        )
      
    
  



wherein in a delay detection system, the signal code sequence Sk is represented by the following equation:





  
    
      
        
          S
          k
        
        =
        
          [
          
            
              
                
                  
                    m
                    
                      mod
                      ⁢
                      
                        
                      
                      ⁢
                      
                        (
                        
                          k
                          /
                          n
                        
                        )
                      
                    
                  
                  ⁢
                  
                    
                      S
                      
                        k
                        -
                        1
                      
                    
                    ⁡
                    
                      (
                      
                        data
                        =
                        
                          1
                          ⁢
                          
                            
                          
                          ⁢
                          or
                          ⁢
                          
                            
                          
                          ⁢
                          0
                        
                      
                      )
                    
                  
                
              
            
            
              
                
                  
                    -
                    
                      m
                      
                        mod
                        ⁢
                        
                          
                        
                        ⁢
                        
                          (
                          
                            k
                            /
                            n
                          
                          )
                        
                      
                    
                  
                  ⁢
                  
                    
                      S
                      
                        k
                        -
                        1
                      
                    
                    ⁡
                    
                      (
                      
                        data
                        =
                        
                          0
                          ⁢
                          
                            
                          
                          ⁢
                          or
                          ⁢
                          
                            
                          
                          ⁢
                          1
                        
                      
                      )
                    
                  
                
              
            
          
        
      
    
    
      
        (
        
          Expression
          ⁢
          
            
          
          ⁢
          3
        
        )
      
    
  



wherein a reference code of a receiving side is denoted by Mj, and a correlation coefficient Ok is represented by the following equation:





  
    
      
        
          O
          k
        
        =
        
          
            ∑
            
              j
              =
              1
            
            n
          
          ⁢
          
            
              S
              
                k
                +
                j
                -
                1
              
            
            ⁢
            
              M
              j
            
          
        
      
    
    
      
        (
        
          Expression
          ⁢
          
            
          
          ⁢
          4
        
        )
      
    
  



in a case where Mj=mj, and the correlation coefficient Ok represents an auto-correlation coefficient which is represented by the following equation:





  
    
      
        
          O
          k
        
        =
        
          
            ∑
            
              j
              =
              1
            
            n
          
          ⁢
          
            
              S
              
                k
                +
                j
                -
                1
              
            
            ⁢
            
              M
              j
            
          
        
      
    
    
      
        (
        
          Expression
          ⁢
          
            
          
          ⁢
          5
        
        )
      
    
  



wherein sub-peaks other than correlation peaks (mod(k/n)≠1) are referred to as side lobes; and
wherein said value of said peak of the one of the absolute auto-correlation side lobes having the smallest value refers to the highest point of said one of the absolute auto-correlation side lobes.

2. A spread spectrum communication receiver according to claim 1, wherein each tap has a coefficient and said coefficient is derived by using an optimization algorithm for peak to side lobe ratio.

3. A spread spectrum communication receiver according to claim 1, wherein the number of taps on the receiver is larger than code length.

4. A spread spectrum communication receiver according to claim 1, wherein a code length of said pseudo noise code is at least 14 and is an odd number.

5. A spread spectrum communication receiver according to claim 1, wherein a code length of said pseudo noise code is 15, 21, 25 or 27.

6. A spread spectrum communication receiver according to claim 1, wherein said spread spectrum communication receiver has a filter function for demodulating a received signal and reducing side lobes of an obtained output matched signal.

7. A spread spectrum communication receiver according to claim 1, wherein said matched filter is used as a demodulating element for demodulating a received signal.

8. A spread spectrum communication receiver according to claim 1, wherein said pseudo noise code is multiplied by a high frequency carrier, and a resultant signal is mixed with a received signal to conduct demodulating of said received signal.

9. A spread spectrum communication receiver according to claim 1, wherein demodulation processing is conducted by using a correlation element for conducting correlation processing between a signal obtained by multiplying said pseudo noise code by a high frequency carrier and a received signal.

10. A spread spectrum communication receiver according to claim 1, wherein the delay detection system is used as a system for detecting a demodulated received signal.

11. A spread spectrum communication receiver according to claim 1, wherein the synchronous detection system is used as a system for detecting a demodulated received signal.