Small low powered digital transmitter for covert remote surveillance

• US 5,712,866 A
• Filed: 07/18/1995
• Issued: 01/27/1998
• Est. Priority Date: 07/18/1995
• Status: Expired due to Fees

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Stein, Louis E., Diviney, Thomas S.
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): GLUCK, JEFFREY WILLIAM
• Application Number:
  US08/503,579
• Time in Patent Office: 924 Days
• Field of Search: 375/206, 375/200
• US Class Current: 375/130
• CPC Class Codes: H04B 1/707 using direct sequence modulation

Abstract

A small low power portable transmitter for remote covert surveillance is disclosed. The transmitter includes a scrambler, forward error correction encoder, differential encoder, spread spectrum system and a modulator. The transmitter may be configured to transmit a single input signal or multiple input signals. The transmitter is powered by a portable single voltage power supply. All digital components of the transmitter may be implemented in a field programmable gate array and the transmitter may be easily modified to accommodate different applications.

Claims

1. A low power portable transmitter for transmitting data signals, comprising:

a. a first input device for converting a first input signal into a first electric signal;

b. a spread spectrum system for increasing the bandwidth of the first electric signal and providing immunity against interference and interception and said spread spectrum system being connected to said first input device; and

c. a modulator for superimposing the spread first electric signal onto a carrier signal for the transmission of the first electric signal and said modulator being connected to said spread spectrum system;

wherein said spread spectrum system is implemented in a programmable logic device.

2. The low power portable transmitter of claim 1 further comprising a scrambler for disarranging the first electric signal according to a known scheme and said scrambler being interposed between said first input device and said spread spectrum system.

3. The low power portable transmitter of claim 2 further comprising:

a. a forward error correction encoder for imposing a code onto the scrambled first electric signal and permitting the detection and correction of errors therein and said forward error correction encoder being connected to said scrambler; and

b. a differential encoder for defeating phase instability in the first electric signal and improving the reception of the first electric signal in a receiver and said differential encoder being interposed between said forward error correction encoder and said spread spectrum system.

4. The low power portable transmitter of claim 3 further comprising a second input device for converting a second input signal into a second electric signal and the second electric signal being applied to said differential encoder.

5. The low power portable transmitter of claim 3 wherein said programmable logic device is a field programmable gate array.

6. The low power portable transmitter of claim 5 wherein said first input device and said scrambler and said forward error correction encoder and said differential encoder and said spread spectrum system and said modulator are implemented in a single housing having dimensions not exceeding 2.5 inches by 1.6 inches and 0.625 inches.

7. The low power portable transmitter of claim 5 wherein said low power transmitter is fabricated of semiconductor material mounted upon dielectric substrates.

8. The low power portable transmitter of claim 5 wherein said scrambler and said forward error correction encoder and said differential encoder and said spread spectrum system and said modulator are powered by a portable single voltage power supply.

9. The low power portable transmitter of claim 5 wherein said scrambler and said forward error correction encoder and said differential encoder and said spread spectrum system and said modulator are implemented in a single housing having dimensions not exceeding 2.5 inches by 1.6 inches and 0.625 inches and powered by a portable single voltage power supply and fabricated of semiconductor material mounted upon dielectric substrates.

10. The low power portable transmitter of claim 1 further comprising a forward error correction encoder for imposing a code onto the first electric signal and permitting the detection and correction of errors therein and said forward error correction encoder being interposed between said first input device and said spread spectrum system.

11. The low power portable transmitter of claim 1 further comprising a differential encoder for defeating phase instability in the first electric signal and improving the reception of the first electric signal in a receiver and said differential encoder being interposed between said first input device and said spread spectrum system.

12. The low power portable transmitter of claim 11 further comprising a second input device for converting a second input signal into a second electric signal and the second electric signal being applied to said differential encoder.

13. The low power portable transmitter of claim 1 wherein said programmable logic device is a field programmable gate array.

14. The low power portable transmitter of claim 1 wherein said first input device and said spread spectrum system and said modulator are implemented in a single housing having dimensions not exceeding 2.5 inches by 1.6 inches and 0.625 inches.

15. The low power portable transmitter of claim 1 wherein said low power portable transmitter is fabricated of semiconductor material mounted upon dielectric substrates.

16. The low power portable transmitter of claim 1 wherein said spread spectrum system and said modulator are powered by a portable single voltage power supply.

17. A method of transmitting a data signal, comprising:

a. converting an input signal into an electric signal;

b. disarranging the electric signal according to a known scheme;

c. adding systematic redundancy to the disarranged electric signal with said adding being performed in a programmable logic device;

d. encoding the redundant electric signal with said encoding being performed in said programmable logic device;

e. spreading the bandwidth of the encoded electric signal with said spreading being performed in said programmable logic device; and

f. modulating a carrier signal with the spread electric signal for the transmission of the electric signal.

18. The method of claim 17 wherein said programmable logic device is a field programmable gate array.