Adaptive expansion table in a digital telephone receiver
First Claim
1. A digital telephone apparatus comprising:
- an adaptive expansion table having as an input a first digital signal comprising n bits and having as an output a second digital signal comprising m bits, where m is greater than n, such that the second digital signal has a resolution that is finer than the resolution of the first digital signal, said adaptive expansion table mapping each of 2n possible input values of the first digital signal to a selected output value comprising m bits, said adaptive expansion table also being configurable to comprise one of a plurality of differing compression maps; and
coupled to the adaptive expansion table, a controller adapted to change the configuration of the adaptive expansion table.
1 Assignment
0 Petitions
Accused Products
Abstract
A digital telephone (60) comprises send equipment (40) and receive equipment (50), coupled via a signal splitter/combiner (61) onto a digital telephone line (62) for communication with a remote party (90). The send equipment (40) comprises an A-law map (12) and a mu-law map (43). Receive equipment (50) comprises an inverse A-law map (14) and an inverse mu-law map (52). Maps (12,43) are selectable by the user (80). Similarly, inverse maps (14,52) are also selectable by the user (80). Receive equipment (50) may further comprise an un-quick-fix module (55) for removing unwanted insertions of quick fixes (25) inserted into the telephone line (62) by international telephone companies. Receive equipment (50) may further comprise a digital signal processor (57), computer (56), a set of pre-stored templates (58) corresponding to possible incoming telephone characteristics, and a caller parameter decipher module (51). In a preferred embodiment of a digital telephone receiver (50), an adaptive expansion table (95) is used to expand the digital signal at the receiver (50) from a relatively coarse resolution to relatively fine resolution. The configuration of the adaptive expansion table (95) is commanded by a control computer (99). Computer (99) is responsive either to a human control operator (80) or to statistics gathered by a statistics gathering module (97). The set of statistics to be gathered by the module (97) can be established by configuring a set of voice and data parameters (98).
79 Citations
24 Claims
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1. A digital telephone apparatus comprising:
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an adaptive expansion table having as an input a first digital signal comprising n bits and having as an output a second digital signal comprising m bits, where m is greater than n, such that the second digital signal has a resolution that is finer than the resolution of the first digital signal, said adaptive expansion table mapping each of 2n possible input values of the first digital signal to a selected output value comprising m bits, said adaptive expansion table also being configurable to comprise one of a plurality of differing compression maps; and coupled to the adaptive expansion table, a controller adapted to change the configuration of the adaptive expansion table. - View Dependent Claims (2, 3, 4, 5)
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6. A method for reducing distortion in a digital telephone apparatus said method comprising the steps of:
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providing an adaptive expansion table having as an input a first digital signal comprising n bits and having as an output a second digital signal comprising m bits, where m is greater than n, such that the second digital signal has a finer resolution than that of the first digital signal, said adaptive expansion table mapping each of 2n possible input values of the first digital signal to a selected output value comprising m bits, said adaptive expansion table also being configurable to comprise one of a plurality of differing compression maps; and coupling to the adaptive expansion table a controller for changing the configuration of the adaptive expansion table in a manner that reduces distortion appearing at the input of the adaptive expansion table. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A method for a telephone end user to overcome incompatibility between a first telephone system using A-law and a second telephone system using mu-law when said telephone end user communicates with a remote party, connected to a telephone system other than the system of the telephone end user, over a telephone line, said method comprising the steps of:
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determining the law that the remote party is using; ascertaining whether an intervening telephone system coupled to said telephone line has inserted an incomplete solution for said incompatibility onto said telephone line; and selecting among a plurality of inverse maps, within receive equipment at the telephone end user'"'"'s location, an inverse map corresponding to said remote party'"'"'s law. - View Dependent Claims (16)
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15. A method for a telephone end user to overcome incompatibility between a first telephone system using A-law and a second telephone system using mu-law when said telephone end user communicates with a remote party, connected to a telephone system other than the system of the telephone end user, over a telephone line, said method comprising the steps of:
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determining the law that the remote party is using; selecting, within send equipment at the telephone end user'"'"'s location, a map corresponding to said remote party'"'"'s law; ascertaining whether an intervening telephone system coupled to said telephone line has inserted an incomplete solution for said incompatibility onto said telephone line; and selecting, within receive equipment at the telephone end user'"'"'s location, an inverse map corresponding to said remote party'"'"'s law. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24)
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Specification