Methods, systems, and devices for techniques for communicating multi-level signals are described. A first device may be configured to communicate signals with a second device according to a modulation scheme. The first device may transmit a first signal to the second device at a first voltage level of the modulation scheme corresponding to a first multi-bit value. The first device may select a second voltage level of the modulation scheme based on a difference between the first voltage level and a third voltage level of the PAM scheme, and may transmit a second signal to the second device at the second voltage level to indicate a second multi-bit value corresponding to the third voltage level. The second device may decode the second signal to determine the second multi-bit value based on receiving the first signal at the first voltage level and the second signal at the second voltage level.

Methods, systems, and devices for techniques for communicating multi-level signals are described. A first device may be configured to communicate signals with a second device according to a modulation scheme. The first device may transmit a first signal to the second device at a first voltage level of the modulation scheme corresponding to a first multi-bit value. The first device may select a second voltage level of the modulation scheme based on a difference between the first voltage level and a third voltage level of the PAM scheme, and may transmit a second signal to the second device at the second voltage level to indicate a second multi-bit value corresponding to the third voltage level. The second device may decode the second signal to determine the second multi-bit value based on receiving the first signal at the first voltage level and the second signal at the second voltage level.

In a PAM-N receiver, sampler reference levels, DC offset and AFE gain may be jointly adapted to achieve optimal or near-optimal boundaries for the symbol decisions of the PAM-N signal. For reference level adaptation, the hamming distances between two consecutive data samples and their in-between edge sample are evaluated. Reference levels for symbol decisions are adjusted accordingly such that on a data transition, an edge sample has on average, equal hamming distance to its adjacent data samples. DC offset may be compensated to ensure detectable data transitions for reference level adaptation. AFE gains may be jointly adapted with sampler reference levels such that the difference between a reference level and a pre-determined target voltage is minimized.

A method for recovering a clock signal from a data signal by using a clock recovery module is described. Edge timings of the data signal are accumulated. The edge timings accumulated are transformed into one reference bit period. A time offset for the reference bit period is determined. A reference clock signal is determined based on the time offset. The number of bits within a system clock of the clock recovery module is determined. The clock signal is recovered based on the reference clock signal and the number of bits. Further, a clock recovery module as well as a computer program are described.

A signal analysis method for analyzing a pulse modulated input signal is described. The signal analysis method includes: receiving the pulse modulated input signal, the input signal including a symbol sequence; recovering a clock signal from the input signal, the clock signal being associated with the input signal; sampling the input signal based on the clock signal, thereby obtaining a set of input signal samples, each of the input signal samples having a certain level being constant over time; determining at least two different levels of input signal samples being associated with different symbols of the symbol sequence; and determining at least one decision threshold based on the at least two different levels determined previously, the decision threshold being associated with a symbol transition of the symbol sequence. Further, a signal analysis apparatus is described.

A signal analysis method for analyzing a pulse modulated input signal is described. The signal analysis method includes: receiving the pulse modulated input signal, the input signal including a symbol sequence; recovering a clock signal from the input signal, the clock signal being associated with the input signal; sampling the input signal based on the clock signal, thereby obtaining a set of input signal samples, each of the input signal samples having a certain level being constant over time; determining at least two different levels of input signal samples being associated with different symbols of the symbol sequence; and determining at least one decision threshold based on the at least two different levels determined previously, the decision threshold being associated with a symbol transition of the symbol sequence. Further, a signal analysis apparatus is described.

A signal analysis method for analyzing a pulse modulated input signal is described. The signal analysis method includes: receiving the pulse modulated input signal, the input signal including a symbol sequence; recovering a clock signal from the input signal, the clock signal being associated with the input signal; sampling the input signal based on the clock signal, thereby obtaining a set of input signal samples, each of the input signal samples having a certain level being constant over time; determining at least two different levels of input signal samples being associated with different symbols of the symbol sequence; and determining at least one decision threshold based on the at least two different levels determined previously, the decision threshold being associated with a symbol transition of the symbol sequence. Further, a signal analysis apparatus is described.

A signal analysis method for analyzing a pulse modulated input signal is described. The signal analysis method includes: receiving the pulse modulated input signal, the input signal including a symbol sequence; recovering a clock signal from the input signal, the clock signal being associated with the input signal; sampling the input signal based on the clock signal, thereby obtaining a set of input signal samples, each of the input signal samples having a certain level being constant over time; determining at least two different levels of input signal samples being associated with different symbols of the symbol sequence; and determining at least one decision threshold based on the at least two different levels determined previously, the decision threshold being associated with a symbol transition of the symbol sequence. Further, a signal analysis apparatus is described.

A memory device as provided may apply a pulse amplitude modulation method to data (DQ) signal transmission/reception and may scale a DQ signal according to an operating frequency condition, so as to improve data transmission performance and effectively improve power consumption. The memory device includes a memory cell array, and a data input/output circuit configured to scale a DQ signal that includes data read from the memory cell array and output the scaled DQ signal. The data input/output circuit is configured to scale the DQ signal based on an n-level pulse amplitude modulation (PAMn) (where n is 4 or a greater integer) with a DQ parameter that corresponds an operating frequency condition and output the DQ signal. Other aspects include memory controllers that communicate with the memory devices, and memory systems that include the memory devices and memory controllers.

A memory device as provided may apply a pulse amplitude modulation method to data (DQ) signal transmission/reception and may scale a DQ signal according to an operating frequency condition, so as to improve data transmission performance and effectively improve power consumption. The memory device includes a memory cell array, and a data input/output circuit configured to scale a DQ signal that includes data read from the memory cell array and output the scaled DQ signal. The data input/output circuit is configured to scale the DQ signal based on an n-level pulse amplitude modulation (PAMn) (where n is 4 or a greater integer) with a DQ parameter that corresponds an operating frequency condition and output the DQ signal. Other aspects include memory controllers that communicate with the memory devices, and memory systems that include the memory devices and memory controllers.