Channel code converter capable of decreasing DC component and channel coding system therefor
AssigneeNEC Corporation
InventorSatoshi Itoi
Life of this patent
Estimating the term…
Abstract
The four tables P, Q, R and S contained in an ROM 2 for 16-24 modulation have a total number of data in which the continuing bits are 2 bits, that is not larger than i bits among the 24 bits, so that the number of continuing bits having the same code is from 2 to 8 bits, so as to have the same characteristics as the (1, 7) code, and to stably lock the PLL. A comparator/selector circuit 5 selects an optimum table out of the tables P, Q, R and S.
Claims29
A channel code converter including table means storing the combinations of channel bits of a bit number larger than a predetermined bit number assigned from the combinations of data bits of said predetermined bit number, in order to convert the codes of data bits of said predetermined bit number into said channel bits using said table means and to record the data according to an NRZ (non-return to zero) rule, wherein said table means comprises:
- a first table for storing the data satisfying predetermined conditions, the data satisfying predetermined conditions being those data having a pattern in which the same bits are continuing by not less than 2 bits in the head portion and in the last portion among the patterns in which the same bits are necessarily continuing by not less than 2 bits except in the head portion and in the last portion of the data stored in the table means among the channel bits, the same bits are necessarily continuing by not more than k bits (k is a positive integer) except in the head portion and in the last portion, and the same bits are continuing by not more than (k−1) bits in the head portion and in the last portion;
- a second table for storing the data of a pattern in which the head portion starts with either “01” or “10” and the same bits are continuing by not less than 2 bits in the last portion among the patterns in which the bits are continuing by not more than (k−1) bits;
- a third table for storing the data in which the same bits are continuing by not less than 2 bits in the head portion, and the last portion ends with “01” and “10” among the patterns in which the bits are continuing by not more than (k−1) bits;
- and
- a fourth table for storing the data of a pattern in which the head portion starts with either “01” or “10” and the last portion ends with either “01” or “10” among the patterns in which the bits are continuing by not more than (k−1) bits;
- said channel code converter further including:
- selection means for selecting any one of said first table to said fourth table so as to start with a channel bit data same as the final bit of one channel bit before and so as to end with a channel bit data same as the start bit of one channel bit after, so that the continuing data bits of a data stream converted inclusive of a connection portion between said channel bits are not smaller than 2 bits but are not larger than k bits.
A channel coding system including table means storing the combinations of channel bits of a bit number larger than a predetermined bit number assigned from the combinations of data bits of said predetermined bit number, in order to convert the codes of data bits of said predetermined bit number into said channel bits using said table means and to record the data according to an NRZ (non-return to zero) rule, wherein said table means comprises:
- a first table for storing the data satisfying predetermined conditions, the data satisfying the predetermined conditions being those data having a pattern in which the same bits are continuing by not less than 2 bits in the head portion and in the last portion among the patterns in which the same bits are necessarily continuing by not less than 2 bits except in the head portion and in the last portion of the data stored in the table unit among the channel bits, the same bits are necessarily continuing by not more than k bits (k is a positive integer) except in the head portion and in the last portion, and the same bits are continuing by not more than (k−1) bits in the head portion and in the last portion;
- a second table for storing the data of a pattern in which the head portion starts with either “01” or “10” and the same bits are continuing by not less than 2 bits in the last portion among the patterns in which the bits are continuing by not more than (k−1) bits;
- a third table for storing the data in which the same bits are continuing by not less than 2 bits in the head portion and the last portion ends with “01” and “10” among the patterns in which the bits are continuing by not more than (k−1) bits;
- and
- a fourth table for storing the data of a pattern in which the head portion starts with either “01” or “10” and the last portion ends with either “01” or “10” among the patterns in which the bits are continuing by not more than (k−1) bits;
- and further including:
- a selection step for selecting any one of said first table to said fourth table so as to start with a channel bit data same as the final bit of one channel bit before and so as to end with a channel bit data same as the start bit of one channel bit after, so that the continuing data bits of a data stream converted inclusive of a connection portion between said channel bits are not smaller than 2 bits but are not larger than k bits.
A recording medium adapted to a channel code converter including table means storing the combinations of channel bits of a bit number larger than a predetermined bit number assigned from the combinations of data bits of said predetermined bit number, said recording medium recording a control program which enables said channel code converter to convert the codes of data bits of said predetermined bit number into said channel bits using said table means and to record the data according to an NRZ (non-return to zero) rule, wherein said table comprises:
- a first table for storing the data satisfying predetermined conditions, the data satisfying the predetermined conditions being those data having a pattern in which the same bits are continuing by not less than 2 bits in the head portion and in the last portion among the patterns in which the same bits are necessarily continuing by not less than 2 bits except in the head portion and in the last portion of the data stored in the table means among the channel bits, the same bits are necessarily continuing by not more than k bits (k is a positive integer) except in the head portion and in the last portion, and the same bits are continuing by not more than (k−1) bits in the head portion and in the last portion;
- a second table for storing the data of a pattern in which the head portion starts with either “01” or “10” and the same bits are continuing by not less than 2 bits in the last portion among the patterns in which the bits are continuing by not more than (k−1) bits;
- a third table for storing the data in which the same bits are continuing by not less than 2 bits in the head portion and the last portion ends with “01” and “10” among the patterns in which the bits are continuing by not more than (k−1) bits;
- and
- a fourth table for storing the data of a pattern in which the head portion starts with either “01” or “10” and the last portion ends with either “01” or “10” among the patterns in which the bits are continuing by not more than (k−1) bits;
- wherein said control program enables said channel code converter to select any one of said first table to said fourth table so as to start with channel bit data same as the final bit of one channel bit before and so as to end with channel bit data same as the start bit of one channel bit after, so that the continuing data bits of a data stream converted inclusive of a connection portion between said channel bits are not smaller than 2 bits but are not larger than k bits.
Dependencies are inferred from the claim text.