According to an aspect, a data inversion circuit configured to perform DBI-DC encoding using a PAM 4 signal may comprise a data generation unit configured to generate input data based on the PAM 4 signal and a data transmission unit comprising, an auxiliary signal generation unit configured to generate an auxiliary signal that determines whether to perform encoding on the input data by analyzing a plurality of data symbols included in the input data, a channel comprising a plurality of data lines and a data encoding unit configured to generate encoded data by performing DBI (data bus inversion) encoding on the data based on the auxiliary signal and to transmit the generated encoded data to a data reception unit via the channel.

According to an aspect, a data inversion circuit configured to perform DBI-AC encoding using a PAM 4 signal may comprise a data generation unit configured to generate input data based on the PAM 4 signal, a channel comprising N data lines, a first auxiliary signal generation unit configured to generate a first auxiliary signal that determines whether to perform a first encoding on the input data based on the number of each of a plurality of data symbols included in the input data, a first data encoding unit configured to generate intermediate data by performing the first encoding on the input data based on the first auxiliary signal, a second auxiliary signal generation unit configured to generate a second auxiliary signal that determines whether to perform a third encoding on the intermediate data by analyzing the relationship between a plurality of data symbols at a current time point and a plurality of data symbols at a previous time point included in the intermediate data and a second data encoding unit configured to generate encoded data by performing the third encoding on the intermediate data based on the second auxiliary signal, and to transmit the generated encoded data to a data reception unit via the channel and the first auxiliary signal and the second auxiliary signal may be combined into one signal and implemented as a PAM 4 signal.

Methods, systems, and devices for data inversion techniques are described to enable a memory device to transmit or receive a multi-symbol signal that includes more than two (2) physical levels. Some portions of some multi-symbol signals may be inverted. A transmitting device may determine to invert one or more data symbols based on one or more parameters. A receiving device may determine that one or more data symbols are inverted and may re-invert the one or more data symbols (e.g., to an original value). When receiving or transmitting a multi-symbol signal, a device may invert or re-invert a data symbol by changing a value of one bit of the data symbol. Additionally or alternatively, a device may invert or re-invert a data symbol of a multi-symbol signal by inverting a physical level of the signal across an axis located between or associated with one or more physical levels.

A receiver that receives a multi-level signal includes a pre-amplifier circuit, a slicer circuit and a decoder circuit. The pre-amplifier circuit generates a plurality of intermediate data signals based on an input data signal and a plurality of reference voltages. The slicer circuit generates a plurality of decision signals based on the plurality of intermediate data signals and a clock signal. The decoder circuit generates output data based on the plurality of decision signals. The pre-amplifier circuit includes a first circuit and a second circuit. The first circuit generates one of the plurality of intermediate data signals based on the input data signal and one of the plurality of reference voltages, and has a first structure. The second circuit generates another one of the plurality of intermediate data signals based on the input data signal and another one of the plurality of reference voltages, and has a second structure different from the first structure.

A sequence detection device includes a decision-feedback equalizer (DFE), a combining circuit, a decision circuit, and a sequence detection circuit. The DFE processes a symbol decision signal to generate a first equalized signal. The combining circuit combines a data signal and the first equalized signal to generate a sample signal. The decision circuit performs hard decision upon the sample signal to generate the symbol decision signal. The sequence detection circuit performs sequence detection upon the data signal to generate and output a symbol sequence. Regarding the sequence detection, the sequence detection circuit selects branches for branch metric calculation according to at least the symbol decision signal.

A PAM4 signal processor calibrates slicing thresholds to reduce bit error rate in a PAM4 clock data recovery circuit by determining a first target value of a first slicing level. The PAM4 signal processor is configured to retrieve the first target value of the first slicing level and sweeps a first reference voltage down from the upper voltage threshold. The PAM4 signal processor is further configured to detect a first filtered output associated with the first reference voltage and determines whether the first filtered output is higher than a target value. Responsive to determining that the first filtered output is higher than the target value, the PAM4 signal processor stores the first reference voltage value

A transceiver circuit includes a receiver front end utilizing a ring oscillator, and a transmitter front end utilizing a pass-gate circuit in a first feedback path across a last-stage driver circuit. The transceiver circuit provides low impedance at low frequency and high impedance at high frequency, and desirable peaking behavior.

A receiver includes an interface configured to receive a data signal based on an n-level pulse amplitude modulation (PAM-n) in which n is an integer equal to or greater than 4. The interface may include an analog-digital converting circuit configured to adjust a reference voltage, for distinguishing second bit data from the data signal in a second section, based on first bit data converted from the data signal in a first section and the first bit data converted from the data signal in the second section, the second section being after the first section.

A receiver includes a plurality of linear equalizers receiving an input signal; and a plurality of samplers configured to sample a plurality of equalization signals output from the plurality of linear equalizers according to a clock signal. Each of the plurality of linear equalizers compares the input signal with a reference voltage among a plurality of reference voltages to determine a level of the input signal.

A signal processing method of a semiconductor device, the method including: receiving a first digital code of a first digital signal; generating a constraint vector; masking the first digital code with a transmitting mask based on the constraint vector; and outputting the masked first digital code and a Data Bus Inversion (DBI) bit of the mask.