Interleaved ADC Polarity Randomization for Offset Spur Reduction
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Solution Overview
Problem
Interleaved ADC circuits in high-bandwidth communication systems suffer from offset mismatches that create undesirable spurs in the output spectrum.
Innovation Solution
A data converter system with a signal generator producing a random binary sequence to control sampling switches that alternate between positive and negative polarities of the input signal, accompanied by an estimation and correction circuit to remove offset voltages, reducing spurs in the output spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple ADC circuits operate in an interleaved manner to achieve high sampling rates, then the sampling rate and bandwidth capability are improved, but offset mismatches among the ADC circuits create undesirable spurs in the output spectrum
Solution Approach 1:
The patent applies dynamics by randomly varying the polarity selection for each ADC circuit at different time instances rather than using a fixed deterministic pattern. This randomization causes the offset mismatches to manifest as random noise rather than periodic spurs, effectively resolving the contradiction between high sampling rate and spectral purity
Solution Approach 2:
The patent changes the parameter of polarity selection from a fixed deterministic value to a randomly varying value. By introducing randomness in the polarity selection parameter, the systematic offset mismatches are transformed into random noise, eliminating the spur generation while maintaining the high sampling rate capability of the interleaved ADC structure
2Use of energy by moving object
If multiple ADC circuits operate in an interleaved manner to optimize energy-speed tradeoffs, then energy efficiency is improved, but sensitivity to metastability increases
Solution Approach 1:
The random polarity switching introduces dynamic variation in the sampling process, which helps to desynchronize and spread out metastability events rather than concentrating them. This dynamic approach maintains the energy efficiency of the interleaved structure while reducing the impact of metastability on overall system reliability
Data Source
AI summary
The present disclosure describes a system with an antenna, a signal generator, data converters, and an aggregator circuit. The antenna is configured to provide an input signal to the data converters. The signal generator is configured to generate a random binary sequence received by the data converters. The data converters include an analog circuit and a digital circuit configured to sample positive and negative polarities of the input signal based on the random binary sequence, reducing an offset tone in an output spectrum produced by the aggregator circuit.