Optical Receive Device Sampling Phase Error Compensation
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Solution Overview
Problem
The implementation of the THP technique in optical transmit devices leads to a loss of signal waveform regularity at the optical receive device, reducing the accuracy of sampling phase error detection and potentially degrading the signal quality of the digital signal.
Innovation Solution
An optical receive device is designed with a coherent receiver, a converter, a scrambler to randomize differential group delay, and an adjustment unit that uses the power envelope method to adjust the sampling frequency and phase of the converter, thereby compensating for sampling phase errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the THP technique is applied at the optical transmit device, then intersymbol interference is compensated, but signal waveform regularity is lost which reduces sampling phase error detection accuracy
Solution Approach 1:
The adjustment unit performs preliminary adjustment of sampling frequency and phase using the power envelope method before the digital signal processing stage. By pre-adjusting the sampling parameters based on the power envelope characteristics of the signal, the system compensates for sampling phase errors that would otherwise be obscured by the THP-induced waveform irregularity, thereby maintaining detection accuracy despite the applied THP technique
Solution Approach 2:
The power envelope method serves as an intermediary mechanism between the THP-processed signal and the sampling phase detection. Instead of directly detecting phase errors from the irregular waveform, the system uses the power envelope characteristics as an intermediate reference that preserves timing information, enabling accurate sampling phase error detection even when the signal waveform regularity is compromised by THP
2Measurement precision
If sampling phase error detection accuracy is reduced due to THP, then signal quality degrades, but adjusting sampling parameters adds device complexity
Solution Approach 1:
The adjustment unit is designed to perform multiple functions: it calculates the power envelope of the digital signal, determines sampling phase errors from the power envelope characteristics, and adjusts both sampling frequency and phase. By consolidating these functions into a single multi-functional unit rather than separate dedicated circuits for each function, the system achieves high sampling phase error detection accuracy while minimizing the increase in device complexity
Data Source
AI summary
An optical receive device includes a coherent receiver that outputs an electrical analog signal corresponding to an optical signal, a converter that converts the electrical analog signal into a digital signal, a scrambler that scrambles a differential group delay (DGD) of the digital signal, and an adjustment unit that receives the digital signal output by the scrambler as an input and adjusts one or both of a sampling frequency and a sampling phase of the converter based on a power envelope (PE) method.