Modulo ADC Phase Conversion for High-Rate Jitter-Limited Sampling
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Solution Overview
Problem
Existing ADC technologies face challenges in achieving high-resolution quantization of wideband analog signals due to timing jitter and limited accuracy, especially in applications requiring very high sampling rates and bandwidths, such as THz wireless communications, and modulo-based ADC strategies lack practical implementations.
Innovation Solution
An ADC apparatus comprising a signal-to-phase conversion unit, ADC unit, and DSP unit, which converts input analog signals into phases of periodic reference signals using bijective or affine transfer functions, followed by ADC operations and digital signal processing to obtain a digital representation, mitigating phase sign ambiguity and enabling high-resolution quantization at high sampling rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional ADC technology is used to achieve high sampling rates, then timing jitter increases, but measurement precision deteriorates
Solution Approach 1:
The patent replaces electronic-based ADC systems with a photonic-based system. The core mechanism uses optical fields (laser pulses) instead of electronic signals to perform sampling. The photonic system uses the interaction between optical fields and analog signals through electro-optic modulators, eliminating the timing jitter limitations inherent in electronic systems and enabling high sampling rates without compromising measurement precision.
2Manufacturing precision
If very high-precision ADC is implemented, then cost and power consumption increase, but manufacturing precision improves
Solution Approach 1:
The patent segments the high-precision ADC function into multiple lower-precision ADCs that operate in parallel on different periodic reference signals. Instead of using one high-precision ADC, the system uses multiple low-precision ADCs (e.g., several 8-bit ADCs) to process M periodic reference signals simultaneously. The final high-resolution digital representation is reconstructed through digital signal processing that combines the outputs of these multiple ADCs, thereby achieving high manufacturing precision while reducing the cost and power consumption associated with implementing a single high-precision ADC.
3Reliability
If modulo-based ADC is used to avoid clipping errors, then device complexity increases, but reliability improves
Solution Approach 1:
The patent implements modulo-based ADC by generating M periodic reference signals with different phases and frequencies. The analog signal is sampled against these periodic references, creating folded versions of the signal that avoid clipping errors. The periodic nature of the reference signals allows the system to capture the analog signal characteristics across multiple cycles, and digital signal processing reconstructs the original signal by analyzing the phase relationships among the periodic samples, thereby improving reliability while managing device complexity through structured periodic sampling.
Data Source
AI summary
A modulo-based ADC implementation is provided and involves converting an input analog signal into phases of other M periodic analog reference signals based on one or more transfer functions, wherein M≥2. The phase of each of the M reference signals comprises a folded signal corresponding to the input analog signal that is amplitude-folded to fall within a required amplitude range. This signal-to-phase conversion allows a modulo operation to be implemented over the input analog signal. Further, the M reference signals are used to obtain M discrete-time digital signals which, in turn, are used to obtain a digital representation of the input analog signal.