This disclosure relates generally to improving data recovery in signal communication and, more particularly, to extracting and decomposing jitter and noise in received n-level Pulse Amplitude Modulation (PAM-n) signals (where n is greater than 1).
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it may be understood that these statements are to be read in this light, and not as admissions of prior art.
Accurately communicating data using high-speed input/output (HSIO) signals is of increasing interest and value to electronic system designers and users. As high-speed input/output data rates exceed 50 gigabits per second (Gbps), n-level Pulse Amplitude Modulation (PAM-n) modulation schemes may be used so that high-speed input/output communication links may more efficiently communicate data with high performance. Pulse Amplitude Modulation (PAM) is a form of signal modulation that communicates data by encoding the data in the amplitude of a series of signal pulses. The amplitude of the series of signal pulses may be varied according to the sample value of the data. PAM-n refers to the number of possible pulse amplitudes in the PAM signal. For example, a PAM-4 signal indicates that there are 4 possible discrete pulse amplitudes.
A communication link used with a PAM-n modulation scheme may scale in an electrical or optical signal amplitude domain while preserving a timing budget. For example, a PAM-4 signal may encode up to two times the information a typical PAM-2 signal may encode while the timing budget for the PAM-4 signal may be approximately the same as the PAM-2 signal. Additionally, the bandwidth of the communication link may be reserved such that cost of a communication system may be maintained or reduced. That is, the additional pulse amplitudes used to encode information in a PAM-n signal may enable a reduction in bandwidth of the corresponding communication link while still maintaining the same data rate, resulting in maintaining or even reducing costs of the communication system.
However, increasing the data rate in the communication system could add jitter and noise to the communication link. Extracting and decomposing jitter and noise components from a signal received over the communication link may thus improve the received signal. While decomposing jitter and noise of a received signal is known for single data level or symbol signals, such decomposition has not been performed on signals of PAM-n modulation schemes, which may be much more complex since jitter and noise are level dependent.