Mapper for high data rate signalling
AssigneeGeneral Data CommInc.
InventorsYuri Goldstein, Yuri Okunev
Life of this patent
Estimating the term…
Abstract
A pulse amplitude modulated (PAM) mapper includes a constellation matrix memory which stores indications of a plurality of different constellations. The constellations are stored as masks of one hundred twenty-eight bits where a bit set to one indicates that the constellation includes the PCM code represented by the corresponding .mu.-law code.
Claims20
In a modem having a transmitter and a receiver, the improvement comprising a constellation memory coupled to at least one of said transmitter and said receiver, said constellation memory having n groups of one hundred twenty-eight bits, where n is an integer greater than one corresponding to the number of constellations stored in said constellation memory, at least a plurality of each group of one hundred twenty-eight bits being set to value "1" and defining a constellation, with each bit set to said value "1" in said constellation memory corresponding to a .mu.-law or A-law level number, wherein said plurality of bits set to value "1" in a first group of one hundred twenty-eight bits is different than said plurality of bits set to value "1" in a second group of one hundred twenty-eight bits.
A PCM modem, comprising:
- a) an interface means for receiving digital data;
- b) an encoder coupled to said interface means for encoding said digital data, said encoder including a PCM mapper having a constellation memory having n groups of one hundred twenty-eight bits, where n is an integer greater than one, at least a plurality of said one hundred twenty-eight bits of a first of said n groups being set to value "1" and defining a first constellation, and at least a plurality of said one hundred twenty-eight bits of a second of said n groups being set to value "1" and defining a second constellation, with each bit set to said value "1" in said constellation memory corresponding to a .mu.-law or A-law level number, and where said plurality of bits set to value "1" in said first group of one hundred twenty-eight bits is different than said plurality of bits set to value "1" in said second group of one hundred twenty-eight bits.
A modem, comprising:
- a) an interface means for receiving digital data;
- b) constellation determination means coupled to said interface means for generating constellation information in response to said digital data;
- and
- c) a constellation memory which stores said constellation information, said constellation memory having n groups of one hundred twenty-eight bits, where n is an integer greater than one, at least a plurality of said one hundred twenty-eight bits of a first of said n groups being set to value "1" and defining a first constellation, and at least a plurality of said one hundred twenty-eight bits of a second of said n groups being set to value "1" and defining a second constellation, with each bit set to said value "1" in said constellation memory corresponding to a .mu.-law or A-law level number, and where said plurality of bits set to value "1" in said first group of one hundred twenty-eight bits is different than said plurality of bits set to value "1" in said second group of one hundred twenty-eight bits.
Dependencies are inferred from the claim text.