Precoded ternary data transmission

Claim 1

Apparatus for communicating a binary data signal over a transmission channel of bandwidth W at an effective binary bit rate that is a nonintegral multiple of the channel symbol rate, comprising means for mapping each possible first block of binary digits taken m at a time into second blocks of n preassigned N-level digits such that 2m is less than Nn and there exists at least one unassigned N-level block, means for precoding N-level digits from said mapping means in accordance with the inverse of the impulse response of said channel such that precoded N-level digits can be decoded from single samples of the received signal, means for exciting said channel with precoded digits from said precoding means at a signaling rate of 2W symbols per second such that channel signals occupy (2N-1) levels, means for reconstructing said N-level digits from said channel signals, means for monitoring N-level digits from said reconstructing means for the presence of said unassigned N-level block therein and producing a framing control signal, means responsive to said framing control signal for partitioning reconstructed N-level digits into n-length blocks such that said unassigned block does not occur within partitioned blocks to be decoded, and means under the control of said partitioning means for translating partitioned blocks of N-level digits into a serial train of binary digits.

Claim 9

The method of communicating a binary data signal train in a precoded multilevel format to achieve an effective signaling rate of three bits per cycle of bandwidth of a communications channel comprising the steps of performing a serial to parallel conversion of serial binary data bits taken three at a time into first blocks, mapping said first blocks of binary data into second blocks of paired ternary digits, there being one nonallowed ternary pair which can only occur between valid second blocks, applying the ternary digits of said second blocks to said communications channel to form precoded multilevel signals at two-thirds the binary signaling rate, recovering at a receiver said ternary digits by a modulo-three reduction of said multilevel signals, monitoring pairs of recovered ternary digits for the occurrence of said nonallowed ternary pair, partitioning responsive to the occurrence of said nonallowed ternary pair said recovered ternary digits into valid second blocks, and decoding properly partitioned second blocks of ternary digits into first blocks of binary digits.

Claim 10

The method of communicating a binary data signal train in a precoded multilevel format to achieve an effective signaling rate of three bits per cycle of bandwidth of a communications channel comprising the steps of performing a serial to parallel conversion of serial binary data bits taken three at a time into first blocks, mapping said first blocks of binary data into second blocks of paired ternary digits, there being one nonallowed ternary pair which can only occur between valid second blocks, applying the ternary digits of said second blocks to said communications channel to form precoded multilevel signals at two-thirds the binary signaling rate, recovering at a receiver said ternary digits by a modulo-three reduction of said multilevel signals, monitoring pairs of recovered ternary digits for the occurrence of said nonallowed ternary pair, partitioning responsive to the occurrence of said nonallowed ternary pair said recovered ternary digits into valid second blocks, and decoding properly partitioned second blocks of ternary digits into first blocks of binary digits.