Subcarrier-Multiplexed Signal Processing With Jitter-Resilient ADCs
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Solution Overview
Problem
High bandwidth signal processing in optical communications is hindered by the sensitivity of ultrahigh speed time-interleaved analog to digital converters (TI-ADCs) to jitter, requiring complex timing recovery and phase lock loop (PLL) systems, and is limited by the size of Fast Fourier Transform modules for dispersion compensation.
Innovation Solution
A system comprising multiple processors with mixers, filters, ADCs, timing recovery modules, and an integrated coherent receiver to process subcarrier-multiplexed signals, which includes a local oscillator controller and subcarrier data aligner to reduce jitter sensitivity and simplify hardware complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If ultrahigh speed time-interleaved analog to digital converters (TI-ADCs) are used for sampling high bandwidth signals, then sampling speed is improved, but jitter sensitivity increases
Solution Approach 1:
The patent divides the high bandwidth signal processing into multiple parallel channels, each handling a portion of the spectrum. By segmenting the signal processing task across multiple lower-speed ADCs rather than using a single ultrahigh-speed ADC, the system achieves the required overall sampling rate while each individual converter operates at a lower, less jitter-sensitive speed.
2Reliability
If complicated timing recovery and phase lock loop (PLL) systems are implemented, then jitter requirements are maintained, but device complexity increases
Solution Approach 1:
The patent extracts and processes each subcarrier signal separately through individual processing chains. By taking out each subcarrier component and handling it independently with simpler timing recovery circuits, the system avoids the need for complex centralized timing recovery and PLL systems that would be required to handle the entire high bandwidth signal as a single channel.
3Reliability
If Fast Fourier Transform module (FFT) size is increased for dispersion compensation, then dispersion compensation performance is improved, but processing complexity increases
Solution Approach 1:
The patent applies segmentation by processing each subcarrier signal separately through its own smaller FFT module for dispersion compensation. Instead of using one large FFT to process the entire high bandwidth signal, the system divides the work into multiple smaller FFT operations on individual subcarriers, achieving the required dispersion compensation performance while keeping each FFT module's size and complexity manageable.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively processes high bandwidth signals with reduced sensitivity to jitter and lower hardware complexity, improving performance and flexibility in handling multiple subcarrier signals.
Implementation Method 1
at least one mixer configured to mix the subcarrier-multiplexed signal with a local oscillator (LO) signal generated by a LO
Data Source
AI summary
The disclosed systems and methods for processing a subcarrier-multiplexed signal comprising: i) mixing the subcarrier-multiplexed signal with a local oscillator (LO) signal; ii) extracting a respective subcarrier signal from the subcarrier-multiplexed signal; iii) sampling the respective subcarrier signal; iv) extracting timing recovery information from the respective subcarrier signal; and v) processing the respective sampled subcarrier signal to extract data from the respective sampled subcarrier signal.