CIRCUIT FOR INTERCONNECTION OF TELEPHONE AND RADIO-TELEPHONE NETWORKS

• US 3,711,647 A
• Filed: 12/22/1970
• Issued: 01/16/1973
• Est. Priority Date: 12/23/1969
• Status: Expired due to Term

• Current Assignee: Marcel-Louis Boyer
• Original Assignee: Marcel-Louis Boyer
• Inventors: Boyer, Marcel-Louis
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US05/100,648
• Time in Patent Office: 756 Days
• Field of Search: 179/2E,15AV,15BZ,15BW,170.2,170.4,170.8,1VC 325/21 343/179
• US Class Current: 455/74.1
• CPC Class Codes: H04B 1/66 for reducing bandwidth of signals; for improving efficiency of transmission H04B1/68 takes precedence

Abstract

Improvement in equipment used for making a telephone connection comprising a path on conductors and a radio path, such equipment being made less sensitive to parasitic disturbances due to a great reduction in the band required for transmitting a control signal supplied by an envelope detector and a syllabic detector.

Claims

1. Network connection circuitry for providing interconnection of a wired telephone network and a radio-telephone network, comprising termination circuit means connected to receive voice frequency signals to be transmitted;

a partial amplitude compressor providing at its output a nonzero dynamic range, a narrow band transmission amplitude detector, and a syllable detector arranged to provide a pulse at the beginning of each syllable in a voice signal, said signal termination circuit means being connected to simultaneously apply said voice frequency signals to respective inputs of said partial amplitude compressor, said amplitude detector and said syllable detector; and

output circuit means for transmitting a summation of the outputs of said partial amplitude compressor, said amplitude detector and said syllable detector.

2. Circuitry as defined in claim 1, wherein said partial amplitude compressor has an output dynamic range substantially equal to 10 decibels.

3. Circuitry as defined in claim 1, wherein said narrow band transmission amplitude detector has a band width extending from 0-2 Hertz.

4. Circuitry as defined in claim 1, wherein said output circuit means includes summation circuit means for combining the outputs of said transmission amplitude detector and said syllable detector, a modulator connected to the output of said summation circuit means and to means generating a sub-carrier frequency located at the upper end of the voice frequency band, further summation circuit means for combining the output of said modulator and the output of said partial amplitude compressor, and a radio-telephone transmitter connected to the output of said further summation circuit means.

5. Circuitry as defined in claim 4, wherein said partial amplitude compressor has an output dynamic range substantially equal to 10 decibels.

6. Circuitry as defined in claim 5, wherein said narrow band transmission amplitude detector has a band width extending from 0-2 Hertz.

7. Network connection circuitry for providing interconnection of a wired telephone network and a radio-telephone network, comprising termination circuit means connected to receive voice frequency signals to be transmitted;

a radio-telephone transmitter including a partial amplitude compressor providing at its output a non-zero dynamic range, a narrow band transmission amplitude detector, and a syllable detector arranged to provide a pulse at the beginning of each syllable in a voice signal, said termination circuit means being connected to simultaneously apply said voice frequency signals to respective inputs of said partial amplitude compressor, said amplitude detector and said syllable detector, and output circuit means for transmitting a summation of the outputs of said partial amplitude compressor, said amplitude detector and said syllable detector; and

a radio-telephone receiver connected to said termination circuit means.

8. Circuitry as defined in claim 7, wherein said output circuit means includes summation circuit means for combining the outputs of said transmission amplitude detector and said syllable detector, a modulator connected to the output of said summation circuit means and to means generating a sub-carrier frequency located at the upper end of the voice frequency band, further summation circuit means for combining the output of said modulator and the output of said partial amplitude compressor, and a radio-telephone transmitter connected to the output of said further summation circuit means.

9. Circuitry as defined in claim 8, wherein said radio-telephone receiver includes a receiver, a first filter connected to the output of said receiver, a second filter connected to the output of said receiver, a narrow band amplitude demodulator connected to the output of said second filter, a syllable test demodulator connected to the output of said second filter, and circuit means for generating voice frequency signals in response to the outputs of said syllable test demodulator, said first filter and said amplitude demodulator.

10. Circuitry as defined in claim 9, wherein said first filter is a band-pass filter having a band width of 300-2,700 Hertz.

11. Circuitry as defined in claim 9, wherein said second filter is a band-pass filter having a band width of 2,700-3,000 Hertz.

12. Circuitry as defined in claim 9, wherein said narrow band amplitude demodulator has a band width of 0-2 Hertz.

13. Circuitry as defined in claim 7, wherein said circuit means for generating voice frequency signals includes an AND-gate having one input connected to the output of said first filter and a second input connected to the output of said syllable test demodulator, an amplitude expander connected to the output of said AND-gate and a variable gain amplifier connected to the output of said expander, the output of said amplitude demodulator being connected to said variable gain amplifier to vary the gain thereof.

14. Circuitry as defined in claim 13, wherein said first filter is a band-pass filter having a band width of 300-2,700 Hertz.

15. Circuitry as defined in claim 14, wherein said second filter is a band-pass filter having a band width of 2,700-3,000 Hertz.

16. Circuitry as defined in claim 15, wherein said narrow band amplitude demodulator hAs a band width of 0-2Hertz.