Incremental ADC Sampling for Wideband Alias Rejection
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Solution Overview
Problem
Traditional signal sampling techniques, especially in extremely wideband receivers, face challenges with aliasing and require substantial hardware and computational resources, which are limiting in detecting weaker signals amidst stronger ones across broad spectra.
Innovation Solution
The method employs incremental sampling with a varying sampling interval defined by Δt n = dt 1 − f + 2f n / n max, where n is the current sample number, dt is the average time step, and f is the variation size, allowing for a deterministic non-uniform sampling grid that reduces computational power and hardware needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional uniform sampling techniques are used, then the sampling process is simple, but the maximum frequency of recoverable signals is limited due to the Nyquist limit and aliasing effects
Solution Approach 1:
The patent combines multiple uniform sampling techniques with non-uniform modulation to create a hybrid sampling approach. Multiple ADCs sample the signal at different rates and phases, and their outputs are combined through digital signal processing to achieve extended bandwidth while maintaining manageable hardware complexity
Solution Approach 2:
The patent transitions from single-dimensional uniform sampling to multi-dimensional sampling by introducing multiple ADCs operating at different sampling rates and phases. This dimensional expansion allows the system to capture signals beyond the Nyquist limit of individual ADCs while using standard sampling hardware
2Speed
If non-uniform sampling techniques are used to defeat aliasing, then the recoverable signal frequency range increases, but substantial hardware and computing resources are required
Solution Approach 1:
The patent divides the wideband signal processing task into multiple segments, each handled by a separate ADC operating at a lower sampling rate. Each ADC processes a portion of the frequency spectrum, and the results are combined digitally. This segmentation reduces the hardware requirements compared to using a single high-speed ADC while still achieving wideband coverage
Solution Approach 2:
The patent introduces digital signal processing as an intermediary that combines the outputs from multiple ADCs. This intermediary processing stage performs the necessary mathematical operations to reconstruct the wideband signal from the multiple lower-rate samples, enabling extended frequency range without requiring any single ADC to operate at extremely high speeds
3Object-affected harmful factors
If multiple uniform sampling techniques are used, then aliasing effects are reduced, but the resources needed to extract signals of interest grow rapidly as the frequency spectrum widens
Solution Approach 1:
The patent applies different sampling strategies to different parts of the frequency spectrum. Each ADC is configured with sampling parameters optimized for its specific frequency range, allowing the system to effectively handle aliasing in each local frequency region while maintaining overall computational efficiency across the entire wideband spectrum
Data Source
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AI summary
A method includes generating (110) a sampling signal having a non-uniform sampling interval (200) and sampling (110) a received signal with an analog-to-digital converter (ADC) (930) using the sampling signal. The method also includes mapping (120) the sampled received signal onto a frequency grid of sinusoids, where each sinusoid has a signal amplitude and a signal phase. The method further includes estimating (120) the signal amplitude and the signal phase for each sinusoid in the frequency grid. In addition, the method includes computing an average background power level and detecting (130) signals with power higher than the average background power level. The non-uniform sampling interval varies predictably.