RF DAC Return-to-Zero Timing for Multi-Nyquist Signal Output
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Solution Overview
Problem
Radio-frequency digital-to-analog converter systems face challenges in generating accurate analog signals across multiple Nyquist zones with minimal interleaving error and maintaining high spurious free dynamic range, especially when operating at full digital rate and handling complex frequency bands.
Innovation Solution
The system employs two digital-to-analog converters operating in a return-to-zero configuration, with a digital controller generating specific codes and timing signals to ensure simultaneous operation in multiple Nyquist zones, minimizing interleaving errors and maintaining high spurious free dynamic range by using a common output and timing system to manage signal transmission and reset operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single digital-to-analog converter operates at full digital rate, then the conversion speed is improved, but interleaving error increases when handling multiple Nyquist zones
Solution Approach 1:
The patent divides the single converter into two parallel digital-to-analog converters (first DAC and second DAC). Each converter handles a specific Nyquist zone with dedicated timing, eliminating interleaving errors while maintaining full digital rate operation. The first converter processes signals for the first Nyquist zone and the second converter processes signals for the second Nyquist zone simultaneously.
2Measurement precision
If multiple digital-to-analog converters are used to reduce interleaving error, then signal accuracy is improved, but device complexity increases
Solution Approach 1:
The patent merges the output signals from the first DAC and second DAC through a common output node. The digital controller coordinates both converters to operate in a return-to-zero configuration with alternating timing, allowing simultaneous multi-Nyquist zone operation while sharing common output infrastructure, thereby reducing overall system complexity.
Solution Approach 2:
The digital controller implements a universal timing system that manages both DACs with a single return-to-zero configuration. The same controller generates timing signals for both converters, coordinating their operation to eliminate interleaving errors while maintaining full digital rate conversion across multiple Nyquist zones.
3Productivity
If converters operate simultaneously without coordinated timing, then productivity is improved, but spurious free dynamic range deteriorates due to interference
Solution Approach 1:
The patent implements periodic action through return-to-zero timing configurations where the first DAC and second DAC operate in alternating cycles. Each converter is activated during specific time intervals coordinated by the digital controller, allowing both to operate at full digital rate while eliminating mutual interference and maintaining high spurious free dynamic range.
Data Source
AI summary
A digital-to-analog converter system has digital-to-analog converters, a common output, and a digital controller for transmitting first codes to one of the converters at a radio-frequency digital rate, and for transmitting second codes to another one of the converters at the same rate. The digital controller includes a timing system for operating each converter at the digital rate in a return-to-zero configuration, such that a signal from the first converter is transmitted to the common output while the second converter is reset, and vice versa. The digital-to-analog converter system can generate a radio-frequency analog signal having signals in first and second Nyquist zones simultaneously.