AM band transmission using multi-tone modulation

• US 6,674,997 B2
• Filed: 08/28/2001
• Issued: 01/06/2004
• Est. Priority Date: 08/28/2001
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hoctor, Ralph Thomas
• Primary Examiner(s): Tran, Pablo N
• Application Number:
  US09/682,387
• Publication Number:
  US 20030054777A1
• Time in Patent Office: 861 Days
• Field of Search: 455/108, 455/466, 455/91, 455/39, 455/41.1, 455/41.2, 455/507, 455/67.11, 455/66.1, 455/344, 379/106.03, 379/10.01, 379/106-4-1, 340/870.04, 340/870.02
• US Class Current: 455/108
• CPC Class Codes: H04H 20/36 for AM broadcasts
• CPC Class Codes: H04H 20/53 Arrangements specially adapted for specific applications, e.g. for traffic information or for mobile receivers
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems

Abstract

A communication system for communicating utility data from a utility distribution network comprises a transmitter for transmitting the utility data. The transmitter comprises a processor that modulates the utility data into a plurality of carrier frequencies. A modulator is connected to the processor and receives the modulated utility data. The modulator modulates the modulated utility data in the AM frequency band forming multi-tone modulated data wherein the transmitter transmits the multi-tone modulated data/transmitted information in the AM frequency band. The communication system also comprises a receiver that receives the transmitted information. The receiver comprises a demodulator that receives the transmitted information and demodulates the transmitted information into a received signal. A processor is connected to the demodulator and receives the demodulated information.

Claims

1. A communication system for communicating information from a utility distribution network, the communication system comprising:

a transmitter for transmitting the information, the transmitter comprising;

a digital signal processor modulating the information into a plurality of carrier frequencies;

a digital-to-analog converter connected to the digital signal processor for converting the modulated information into an analog signal; and

a wide band radio frequency (RF) modulator connected to the digital-to-analog converter and receiving the analog signal, the wide band RF modulator modulating the analog signal in an AM frequency band wherein the multi-tone modulated analog signal is transmitted in the AM frequency band by the transmitter wherein the transmitted multi-tone modulated analog signal comprises transmitted information;

a receiver for receiving the transmitted information from the transmitter, the receiver comprising;

a wide band radio frequency (RF) demodulator for receiving the transmitted information, the wide band RF demodulator demodulating the transmitted information into a received analog signal;

an analog-to-digital converter connected to the wide band RF demodulator for converting the received analog signal to received digital data; and

a digital signal processor connected to the analog-to-digital converter and receiving the received digital data, the digital signal processor constructing the received digital data and forming received information.

2. The communication system of claim 1 wherein the digital signal processor of the transmitter modulates the information using multi-tone modulation.

3. The communication system of claim 1 wherein the transmitter further comprising a storage device connected to the digital signal processor for storing a sampled signal waveform and wherein the information comprises a message bit.

4. The communication system of claim 3 wherein the digital signal processor of the transmitter further comprising:

a multiplier connected to the storage device for multiplying the sampled signal waveform with the message bit to form a product output;

at least one modulator connected to the multiplier wherein the at least one modulator uses a plurality of complex sinusoids corresponding to a plurality of multi-tone modulation frequencies to modulate the product output into the plurality of carrier frequencies; and

a summer connected to each of the at least one modulators for adding each of the modulated product outputs together to generate a wideband signal having a plurality of tones modulated by the message bit.

5. The communication system of claim 4 wherein the signaling waveform has a bandwidth between about 0.25 kHz and 1.0 kHz.

6. The communication system of claim 4 wherein the plurality of carrier frequencies ranges between about 8 to 32 frequencies and each of the plurality of multi-tone modulation frequencies being situated midway between AM radio broadcast frequencies.

7. The communication system of claim 1 wherein the wide band RF modulator of the transmitter modulates the analog signal in a frequency midway between AM radio broadcast frequencies.

8. The communication system of claim 1 wherein the transmitter further comprising a storage device connected between the digital signal processor and the digital-to-analog converter for storing the modulated information.

9. The communication system of claim 1 wherein the receiver further comprising at least one bandpass filter connected to the wide band RF demodulator for filtering the received analog signal.

10. The communication network of claim 9 wherein each at least one bandpass filter passes a signal corresponding to one of the plurality of carrier frequencies.

11. The communication system of claim 1 wherein wide band RF demodulator demodulates the transmitted AM modulated analog signal in at least part of the AM frequency band.

12. The communication system of claim 1 wherein the receiver provides feedback to the transmitter indicative of a signal to noise ratio of the AM band frequency in which the analog signal is modulated and transmitted.

13. The communication system of claim 1 wherein the transmitter further comprising an antenna connected to the digital signal processor and wherein the receiver further comprising an antenna connected to the wide band RF demodulator.

14. A communication system for communicating information, the communication system comprising:

a transmitter for transmitting the information, the transmitter comprising;

a processor modulating the information into a plurality of carrier frequencies; and

a modulator connected to the processor and receiving the modulated utility data, the modulator modulating the modulated utility data in an AM frequency band forming multi-tone modulated data wherein the multi-tone modulated data is transmitted in the AM frequency band by the transmitter and the transmitted multi-tone modulated data comprises transmitted information;

a receiver for receiving information from the transmitter, the receiver comprising;

a demodulator for receiving the transmitted information, the demodulator demodulating the transmitted information into a received signal; and

a processor connected to the demodulator and receiving the received signal, the processor constructing the received signal and forming received information.

15. The communication system of claim 14 wherein the processor of the transmitter comprises a digital signal processor and wherein the transmitter further comprising a digital-to-analog converter connected between the digital signal processor and the modulator for converting the modulated utility data into an analog signal.

16. The communication system of claim 15 wherein the processor of the receiver comprises a digital signal processor and wherein the receiver further comprising an analog-to-digital converter connected between the demodulator and the digital signal processor for converting the received signal into received digital data.

17. The communication system of claim 16 wherein the transmitter further comprising a storage device connected to the processor for storing a sampled signal waveform and wherein the information comprises a message bit.

18. The communication system of claim 17 wherein the digital signal processor of the transmitter further comprising:

a multiplier connected to the storage device for multiplying the sampled signal waveform with the message bit to form a product output;

at least one modulator connected to the multiplier wherein the at least one modulator uses a plurality of complex sinusoids corresponding to a plurality of multi-tone modulation frequencies to modulate the product output into the plurality of carrier frequencies; and

a summer connected to each of the at least one modulators for adding each of the modulated product outputs together to generate a wideband signal having a plurality of tones modulated by the message bit.

19. The communication system of claim 18 wherein the signaling waveform has a bandwidth between about 0.25 kHz and 1.0 kHz.

20. The communication system of claim 18 wherein the plurality of carrier frequencies ranges between about 8 to 32 frequencies and each of the plurality of multi-tone modulation frequencies being situated midway between AM radio broadcast frequencies.

21. The communication network of claim 18 wherein the receiver further comprising at least one bandpass filter connected between the demodulator and the analog-to-digital converter for filtering the received signal.

22. The communication network of claim 21 wherein each at least one bandpass filter passes a signal corresponding to one of the plurality of carrier frequencies.

23. The communication system of claim 14 wherein demodulator demodulates the transmitted information in at least part of the AM frequency band.

24. The communication system of claim 14 wherein the modulator of the transmitter modulates the information in a frequency midway between AM radio broadcast frequencies.

25. The communication system of claim 14 wherein the receiver provides feedback to the transmitter indicative of a signal to noise ratio of the AM band frequency in which the information is modulated and transmitted.

26. The communication system of claim 14 wherein the transmitter further comprising an antenna connected to the processor and wherein the receiver further comprising an antenna connected to the demodulator.

27. The communication system of claim 14 wherein the processor of the transmitter modulates the information using multi-tone modulation.