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 circuit for receiving serial data. In some embodiments, the circuit has an input for receiving an analog input signal, and includes a first sampler for sampling the analog input signal relative to a first reference voltage, a second sampler for sampling the analog input signal relative to a second reference voltage, and a reference voltage control circuit. The second reference voltage may have a sign opposite to that of the first reference voltage; and the reference voltage control circuit may be configured to adjust the first reference voltage or the second reference voltage, based on a first sample of the analog input signal, the first sample having been taken at a sampling time corresponding to a one bit, in the serial data, preceded by a one bit and followed by a one bit.

A clock recovery device (10), including: a signal conversion circuit (20) that sequentially converts two consecutive symbols of a 2n+1 value (n is a natural number) pulse amplitude modulation signal to one symbol of an NRZ (Non Return to Zero) signal; and a clock recovery circuit (30) that generates a recovery clock signal from the NRZ signal converted by the signal conversion circuit. The signal conversion circuit converts the two consecutive symbols: to 0, when a second symbol is n−1 or less; to 1, when the second symbol is n+1 or more; to 0, when a first symbol is n−1 or less and the second symbol is n; to 1, when a first symbol is n+1 or more and the second symbol is n; to a conversion result of previous two symbols, when both of the two consecutive symbols are n.

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 semiconductor device including a signal generator and decoding and timing skew adjusting circuit is provided. The signal generator is configured to receive n multi-level signals having m signal levels and convert the n multi-level signals into n*(m1) single level signals having two signal levels. The decoding and timing skew adjusting circuit is configured to receive the single level signals, perform a predefined operation on the single level signals to generate an output signal, and compensate for timing skew between the n multi-level signals, using the single level signals. The n and m are natural numbers, where n>=2 and m>=3.

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.

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.

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.

System and method of demodulation by adapting constellation values based on statistic distributions of received data symbols. To determine an adapted constellation, an expected ratio of received symbols with values in a certain range is preset based on an expected statistic distribution of data symbols across the multiple constellations. For a set of received symbols, a count ratio of symbols falling in a first range to all the symbols in the set is compared with the expected ratio, where the first range is defined as below a first value. The first value is repeatedly adjusted to adjust the first range until the count ratio equals the expected ratio. The final first value is then designated as the optimal adapted constellation.