PAM-4 Encoder Coding with Shaping Parity for CDR and Eye Openness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multi-level signaling systems, such as PAM-4, suffer from reduced eye pattern openness, making them susceptible to jitter, noise, and distortion, which degrades clock and data recovery (CDR) performance.
Innovation Solution
A semiconductor device employs an encoder that adds shaping parity bits to user data, uses a polar code generator matrix for encoding, and calculates metric values to select encoded data, while the receiver decodes the signal to restore user data, thereby improving CDR and eye pattern performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-level signaling (PAM-4) is used to transmit more information with a single signal, then data transmission efficiency is improved, but eye pattern openness is reduced making the system more susceptible to jitter, noise and distortion
Solution Approach 1:
The patent applies parameter changes by modifying the transition pattern of multi-level signals through encoding. Specifically, it controls the frequency and pattern of level transitions (particularly between adjacent levels) to reduce susceptibility to jitter and noise while maintaining the 4-level signaling structure for high data transmission efficiency
Solution Approach 2:
The patent uses preliminary action by pre-processing the data sequence through encoding before transmission. The encoder modifies the data sequence to create a transition pattern that is optimized for multi-level signaling, thereby preemptively reducing the impact of jitter and noise on eye pattern openness before the signal is transmitted
2Productivity
If multi-level signaling is used to improve data transmission efficiency, then more information is transmitted with a single signal, but clock and data recovery (CDR) performance is degraded
Solution Approach 1:
The patent changes the temporal parameters of the signal by controlling level transition patterns. By reducing the frequency of transitions between adjacent levels and optimizing the distribution of transition types, the encoded signal provides better timing references for CDR while maintaining high data transmission efficiency
3Ease of manufacture
If conventional encoding is used in multi-level signaling, then implementation is simpler, but susceptibility to jitter, noise and distortion increases
Solution Approach 1:
The patent modifies the transition pattern parameters of the encoded signal to reduce susceptibility to harmful factors. By controlling the frequency of transitions between adjacent levels and optimizing the distribution of different transition types, the encoding scheme reduces the impact of jitter, noise and distortion while maintaining implementation feasibility
Data Source
AI summary
Disclosed is a semiconductor device transmitting a multi-level signal including: an encoder encoding user data into encoded data; and a transmission driver converting the encoded data into a multi-level signal. The encoder includes: a bit adder generating a codeword by adding at least one shaping parity bit to the user data; an encoding operator generating candidate encoded data by performing an encoding operation on the codeword; a metric operator calculating metric values by using a metric operation equation for the candidate encoded data; and a metric searcher searching for the metric values to select the encoded data from the candidate encoded data and provide the selected encoded data to the transmission driver.