Signalling system

• US 20050053122A1
• Filed: 10/21/2004
• Published: 03/10/2005
• Est. Priority Date: 01/16/1997
• Status: Active Grant

• Current Assignee: Intrasonics SARL
• Original Assignee: Scientific Generics Limited (Science Group Plc)
• Inventors: Barclay, Michael John
• Granted Patent: US 7,796,676 B2
• Time in Patent Office: Days
• US Class Current: 375/141
• CPC Class Codes: G06K 17/0022 arrangements or provisious for transferring data to distant stations, e.g. from a sensing device "transfer between computer elements G06F13/00 "; data-transmission H04L
• CPC Class Codes: G06Q 20/20 Point-of-sale [POS] network systems
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 11/00 Transmission systems employing sonic, ultrasonic or infrasonic waves
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker

Abstract

A signalling system is provided which can be used to update the prices of goods which are electronically displayed on supermarket shelves (1). The signalling system comprises a first signalling device having an input terminal for receiving electrical message data received from a central computer system (5), a spread spectrum encoder for encoding the received message data and an electroacoustic converter (11) for converting the encoded data into corresponding acoustic signals and for transmitting the acoustic signals into a transmission medium. The signalling system also comprises a second signalling device (3) having means for receiving acoustic signals from said transmission medium and for converting the received acoustic signals into corrresponding electrical signals, a spread spectrum decoder for decoding the received signals and a message regenerator for regenerating the message data transmitted by the first signalling device from the signals output by the decoder.

Claims

1-50. -50. (Cancelled)

51. A signalling system comprising:

a first signalling device comprising;

(i) an input terminal operable to receive electrical message data having a power spectrum which lies substantially over a first bandwidth, (ii) a spread spectrum encoder operable to spread the power spectrum of the message data substantially over a second bandwidth which is greater than the first bandwidth and which extends over a frequency band which is audible to humans; and

(iii) an electroacoustic convertor operable to convert the data output by said spread spectrum encoder into corresponding acoustic signals and for transmitting the acoustic signals into the atmosphere; and

a second signalling device comprising;

(i) an acoustoelectric converter operable to receive acoustic signals from the atmosphere and to convert the received acoustic signals into corresponding electrical signals;

(ii) a spread spectrum decoder operable to despread the power spectrum of the received signals;

(iii) a message regenerator operable to regenerate the message data transmitted by said first signalling device from the despread signals output by said spread spectrum decoder; and

(iv) an output operable to output a human discernable response in dependence upon the regenerated message data.

52. A system according to claim 51, wherein said output comprises a display for outputting a visible response in dependence upon the regenerated message data.

53. A system according to claim 51, wherein said output comprises a loudspeaker for outputting an audible response in dependence upon the regenerated message data.

54. A system according to claim 51, wherein said spread spectrum encoder is operable to combine the bits of the message data with a pseudo-noise code.

55. A system according to claim 54, wherein said spread spectrum encoder is operable to replace each bit of the message data with a pseudo-noise code or an inverse of the pseudo-noise code in dependence upon whether the message bit is a one or a zero.

56. A system according to claim 55, wherein the message bits are represented as plus one or minus one, and wherein said spread spectrum encoder comprises a code generator for generating said pseudo-noise code and a mixer for multiplying the code generated by said code generator with said message bits

57. A system according to claim 54, wherein said spread spectrum decoder is operable to combine the received signal with the same pseudo-noise code used in the spread spectrum encoder.

58. A system according to claim 57, wherein said spread spectrum decoder is operable to multiply the received signal with said pseudo-noise code.

59. A system according to claim 58, wherein said spread spectrum decoder is operable to correlate the received signal with said pseudo-noise code.

60. A system according to claim 51, wherein said first signalling device further comprises a power monitor operable to monitor the power level of the ambient noise and an adjuster operable to adjust the power level of the transmitted acoustic signals in dependence upon the monitored power level of the ambient noise.

61. A system according to claim 60, wherein said monitor is operable to monitor the noise in a number of frequency sub-bands extending over said second bandwidth, and wherein said adjuster is operable to adjust the power level of the transmitted acoustic signals independently in each of said frequency sub-bands.

62. A system according to claim 61, wherein said adjuster is operable to adjust the power level in each sub-band in dependence upon the sensitivity of the human ear to acoustic signals in that sub-band.

63. A system according to claim 60, wherein said spread spectrum encoder is operable to combine the bits of the message data with a pseudo-noise code and wherein said adjuster is operable to adjust said power level of the transmitted acoustic signals in dependence upon the length of code used by said spread spectrum encoder and upon the distance between the first and second signalling devices.

64. A system according to claim 63, wherein said adjuster is operable to adjust the power level of the transmitted acoustic signal so that the power level of the transmitted acoustic signal at the second signalling device is below the power level of the ambient noise.

65. A system according to claim 51, wherein said second signalling device further comprises:

i) a signal generator for generating message data having a power spectrum which lies substantially over a first bandwidth;

ii) a power spreader operable to spread the power spectrum of the message data substantially over a second bandwidth which is greater than the first bandwidth and which extends over a frequency band which is audible to humans; and

iii) a converter operable to convert the data output by said spreader into corresponding acoustic signals and operable to transmit the acoustic signals into the atmosphere; and

wherein said first signalling device further comprises;

i) a receiver operable to receive acoustic signals from the atmosphere and to convert the received acoustic signals into corresponding electrical signals;

ii) a power despreader operable to despread the power spectrum of the received signals; and

iii) a message regenerator operable to regenerate the message data transmitted by the second signalling device from the despread signals output by the despreader.

66. A system according to claim 65, wherein the spreader of the second signalling device is operable to spread the message data using a pseudo-noise code which is different from a pseudo-noise code used to spread the message signal by the spread spectrum encoder of the first signalling device.

67. A system according to claim 65, wherein the second signalling device further comprises a monitor operable to monitor the power level of the ambient noise at the second signalling device and an adjuster operable to adjust the power level of the acoustic signals transmitted by said second signalling device in dependence upon the monitored power level of the ambient noise at the second signalling device.

68. A system according to claim 67, wherein at least one of said first and second signalling devices is operable to transmit message data indicative of the power level of the ambient noise monitored at that signalling device to the other signalling device for use in controlling the power level of the acoustic signal transmitted by the other signalling device.

69. A system according to claim 67, wherein said first signalling device further comprises a power monitor operable to monitor the power level of the ambient noise and an adjuster operable to adjust the power level of the transmitted acoustic signals in dependence upon the monitored power level of the ambient noise and wherein the adjuster of at least one of said signalling devices is operable to control the power level of the acoustic signals transmitted by that signalling device in dependence upon the message data received from the other signalling device.

70. A system according to claim 67, wherein said first signalling device further comprises a power monitor operable to monitor the power level of the ambient noise and an adjuster operable to adjust the power level of the transmitted acoustic signals in dependence upon the monitored power level of the ambient noise and wherein the adjuster of at least one of said first and second signalling devices is operable to adjust the power level of the acoustic signals transmitted by that signalling device in dependence upon the bit error rate of the message data received from the other signalling device.

71. A system according to claim 51, wherein said first signalling device comprises a signal generator operable to generate said message data.

72. A system according to claim 71, wherein said signal generator of said first signalling device is operable to generate said message data in dependence upon sensor data received from a sensor.

73. A system according to claim 71, wherein said signal generator of said first signalling device is operable to generate said message data in dependence upon user input.

74. A system according to claim 51, comprising a plurality of said second signalling devices, each operable to receive message data transmitted by said first signalling device.

75. A system according to claim 74, wherein said first signalling device is operable to transmit message data to a selected one or more of said second signalling devices.

76. A system according to claim 75, wherein each of said second signalling devices is independently addressable.

77. A system according to claim 51, comprising a plurality of said first signalling devices, each operable to transmit message data to the second signalling device.

78. A system according to claim 51, wherein said electroacoustic converter comprises one or more spaced loudspeakers.

79. A signalling device comprising:

a receiver operable to receive a spread spectrum acoustic signal having a bandwidth which extends over a frequency band which is audible to humans;

a spread spectrum decoder operable to despread the power spectrum of the received signals;

a message regenerator operable to regenerate message data carried by the spread spectrum acoustic signal from the despread signals output by said spread spectrum decoder; and

an output operable to output a human discernible response in dependence upon the regenerated message data.

80. A signalling device according to claim 79, wherein said output comprises a display for outputting a visible response in dependence upon the regenerated message data.

81. A signalling device according to claim 79, wherein said output comprises a loudspeaker for outputting an audible response in dependence upon the regenerated message data.

82. A device according to claims 79, wherein said spread spectrum decoder is operable to combine the received signal with a pseudo-noise code used to generate the spread spectrum acoustic signal.

83. A device according to claim 82, wherein said spread spectrum decoder is operable to multiply the received signal with said pseudo-noise code.

84. A device according to claim 82, wherein said spread spectrum decoder is operable to correlate the received signal with said pseudo-noise code.

85. A signalling device according to claim 79, further comprising:

a signal generator operable to generate message data having a power spectrum which lies substantially over a first bandwidth;

a power spreader operable to spread the power spectrum of the message data substantially over a second bandwidth which is greater than the first bandwidth; and

a convertor operable to convert the data output by said power spreader into a corresponding acoustic signal and to transmit the acoustic signal into a transmission medium.

86. A device according to claim 85, wherein the power spreader is operable to spread the message data using a pseudo-noise code which is different from a pseudo-noise code used by said spread spectrum decoder.

87. An atmospheric acoustic signalling method comprising:

at a first signalling device;

i) receiving electrical message data having a power spectrum which lies substantially over a first bandwidth;

ii) spreading the power spectrum of the message data substantially over a second bandwidth which is greater than the first bandwidth and which extends over a frequency band which is audible to humans; and

iii) converting the data generated by said spreading step into corresponding acoustic signals and transmitting the acoustic signals into the atmosphere; and

at a second signalling device;

i) receiving acoustic signals from the atmosphere and converting the received acoustic signals into corresponding electrical signals;

ii) despreading the power spectrum of the received signals;

iii) regenerating the message data transmitted by the first signalling device from the despread signals generated by the despreading step; and

iv) outputting a human discernable response in dependence upon the regenerated message data.

88. A method according to claim 87, wherein said outputting step comprises the step of outputting a visible response in dependence upon the regenerated message data.

89. A method according to claim 87, wherein said outputting step outputs an audible response in dependence upon the regenerated message data.