Signalling system

• US 7,796,676 B2
• Filed: 10/21/2004
• Issued: 09/14/2010
• Est. Priority Date: 01/16/1997
• Status: Expired due to Term

• Current Assignee: Intrasonics SARL
• Original Assignee: Intrasonics Limited (Ipsos SA)
• Inventors: Barclay, Michael John
• Primary Examiner(s): Payne; David C
• Assistant Examiner(s): Dsouza; Adolf
• Application Number:
  US10/970,332
• Publication Number:
  US 20050053122A1
• Time in Patent Office: 2,154 Days
• Field of Search: 367/134, 367/132, 375/130, 375/141, 380/37, 704/200.1
• US Class Current: 375/141
• CPC Class Codes: G06K 17/0022 arrangements or provisions 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. The signaling system may include a first signalling device having an input terminal for receiving electrical message data received from a central computer system, a spread spectrum encoder for encoding the received message data and an electroacoustic converter for converting the encoded data into corresponding acoustic signals and for transmitting the acoustic signals from the transmission medium and for converting the received acoustic signals into corresponding 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. An acoustic data communication system comprising:

a first acoustic data communications 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 having a bandwidth that extends over a frequency band audible to humans and for transmitting the acoustic signals into the atmosphere; and

a second acoustic data communications 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 acoustic data communications device from the despread signals output by said spread spectrum decoder;

(iv) a processor operable to process the regenerated message data and operable to output a control signal in dependence upon the regenerated message data and (v) an output coupled to the processor and operable to receive the control signal and to output a human discernable response in dependence upon the control signal.

2. A system according to claim 1, wherein said output comprises a display for outputting a visible response in dependence upon the control signal.

3. A system according to claim 1, wherein said output comprises a loudspeaker for outputting an audible response in dependence upon the control signal.

4. A system according to claim 1, wherein said spread spectrum encoder is operable to combine the bits of the message data with a pseudo-noise code.

5. A system according to claim 4, 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.

6. A system according to claim 5, 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.

7. A system according to claim 4, wherein said spread spectrum decoder is operable to combine the received signal with the same pseudo-noise code used in the spread spectrum encoder.

8. A system according to claim 7, wherein said spread spectrum decoder is operable to multiply the received signal with said pseudo-noise code.

9. A system according to claim 8, wherein said spread spectrum decoder is operable to correlate the received signal with said pseudo-noise code.

10. A system according to claim 1, wherein said first acoustic data communications 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.

11. A system according to claim 10, 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.

12. A system according to claim 11, 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.

13. A system according to claim 10, 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 acoustic data communications devices.

14. A system according to claim 13, 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 acoustic data communications device is below the power level of the ambient noise.

15. A system according to claim 1, wherein said second acoustic data communications 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 acoustic data communications 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 acoustic data communications device from the despread signals output by the despreader.

16. A system according to claim 15, wherein the spreader of the second acoustic data communications 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 acoustic data communications device.

17. A system according to claim 15, wherein the second acoustic data communications device further comprises a monitor operable to monitor the power level of the ambient noise at the second acoustic data communications device and an adjuster operable to adjust the power level of the acoustic signals transmitted by said second acoustic data communications device in dependence upon the monitored power level of the ambient noise at the second acoustic data communications device.

18. A system according to claim 17, wherein at least one of said first and second acoustic data communications devices is operable to transmit message data indicative of the power level of the ambient noise monitored at that acoustic data communications device to the other acoustic data communications device for use in controlling the power level of the acoustic signal transmitted by the other acoustic data communications device.

19. A system according to claim 17, wherein said first acoustic data communications 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 acoustic data communications devices is operable to control the power level of the acoustic signals transmitted by that acoustic data communications device in dependence upon the message data received from the other acoustic data communications device.

20. A system according to claim 17, wherein said first acoustic data communications 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 acoustic data communications devices is operable to adjust the power level of the acoustic signals transmitted by that acoustic data communications device in dependence upon the bit error rate of the message data received from the other acoustic data communications device.

21. A system according to claim 1, wherein said first acoustic data communications device comprises a signal generator operable to generate said message data.

22. A system according to claim 21, wherein said signal generator of said first acoustic data communications device is operable to generate said message data in dependence upon sensor data received from a sensor.

23. A system according to claim 21, wherein said signal generator of said first acoustic data communications device is operable to generate said message data in dependence upon user input.

24. A system according to claim 1, comprising a plurality of said second acoustic data communications devices, each operable to receive message data transmitted by said first acoustic data communications device.

25. A system according to claim 24, wherein said first acoustic data communications device is operable to transmit message data to a selected one or more of said second acoustic data communications devices.

26. A system according to claim 25, wherein each of said second acoustic data communications devices is independently addressable.

27. A system according to claim 1, comprising a plurality of said first acoustic data communications devices, each operable to transmit message data to the second acoustic data communications device.

28. A system according to claim 1, wherein said electroacoustic converter comprises one or more spaced loudspeakers.

29. An atmospheric acoustic data communication method comprising:

receiving electrical message data having a power spectrum which lies substantially over a first bandwidth at a first acoustic data communications device;

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 at the first acoustic data communications device;

converting the data generated by said spreading step into corresponding acoustic signals having a bandwidth that extends over a frequency band audible to humans and transmitting, via a loudspeaker, the acoustic signals into the atmosphere at the first acoustic data communications device;

receiving, via a microphone, acoustic signals from the atmosphere and converting the received acoustic signals into corresponding electrical signals at a second acoustic data communications device;

despreading the power spectrum of the received signals at the second acoustic data communications device;

regenerating the message data transmitted by the first acoustic data communications device from the despread signals generated by the despreading step at the second acoustic data communications device;

processing the regenerated message data using a processor at the second acoustic communications device and outputting a control signal in dependence upon the regenerated message data; and

outputting a human discernable response at the second acoustic data communications device in dependence upon the control signal.

30. A method according to claim 29, wherein said outputting step comprises the step of outputting a visible response in dependence upon the control signal.

31. A method according to claim 29, wherein said outputting step outputs an audible response in dependence upon the control signal.