Transmission method for transmitting voice and data information over telephone line and device for implementing said method
First Claim
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1. A transmission method for simultaneously transmitting voice signals covering a given frequency bandwidth and pure data provided by digital terminals over the same telephone line, said method including:
- processing the voice signals for extracting a low frequency band analog signal, i.e., a base band signal and characteristic voice parameters therefrom;
digitally coding said characteristic voice parameters;
multiplexing said pure data with said digitally coded characteristic parameters;
converting the multiplexed data into analog signal(s);
adding said analog converted signal(s) to said analog base band; and
transmitting said added signal(s) over the telephone line(s).
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Abstract
The method allows voice and data information to be concentrated over a reduced number of telephone lines. It consists mainly in processing each voice signal to extract therefrom a so-called analog base band signal and digitally coded characteristic parameters. Said parameters are then multiplexed with pure data and submitted to a modulation operation. The analog signal resulting from the modulation is then added to the base band before being transmitted over a telephone line.
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Citations
13 Claims
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1. A transmission method for simultaneously transmitting voice signals covering a given frequency bandwidth and pure data provided by digital terminals over the same telephone line, said method including:
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processing the voice signals for extracting a low frequency band analog signal, i.e., a base band signal and characteristic voice parameters therefrom; digitally coding said characteristic voice parameters; multiplexing said pure data with said digitally coded characteristic parameters; converting the multiplexed data into analog signal(s); adding said analog converted signal(s) to said analog base band; and transmitting said added signal(s) over the telephone line(s). - View Dependent Claims (2, 3, 4, 5, 6)
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7. A transmission method wherein information provided by N voice sources are concentrated over n telephone lines with n less than N, said method including the operations of:
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filtering the speech signals provided by said voice sources for individually extracting so-called low frequency analog base band signals therefrom; extracting from each of said speech signals so-called characteristic speech parameters and digitally coding said parameters; grouping the various base band signals into predetermined groups; adding together the base band signals within each of said groups and transmitting the added base band signals over a first same telephone line; grouping the characteristic speech parameters into predetermined groups; multiplexing together the parameters of the same group; submitting the multiplexed parameters of each group to modulation operation; and
,transmitting the signal resulting from said modulation over a second same telephone line. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A device for transmitting voice signals and pure data provided by digital terminals over the same telephone line, including:
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filtering means fed with said voice signals and deriving therefrom a so-called base band analog information and high-frequency sub-bands information; energy measuring means responsive to said filtering means for deriving energy information relative to the energies contained within said base band and within each of said subbands; energy normalizing means responsive to said energy measuring means for normalizing said subband energies to the base band energy; coding means responsive to said normalizing means for digitally coding said normalized energies and deriving characteristic speech parameters therefrom; multiplexing means connected to said coding means and to at least one source of pure data; modulating means connected to said multiplexing means, and, adding means responsive to said filtering means and to said modulating means for adding said base band information to the signal supplied by said modulating means, and for feeding said telephone line.
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Specification