Direct RF D-A Conversion Using Phase-Shifted Parallel Sample Streams
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Solution Overview
Problem
Conventional wireless communication devices face challenges in integrating high-speed digital and analog circuits due to the shrinking size of digital circuits, which complicates the generation of high-resolution analog carrier waveforms required for multiple frequency bands.
Innovation Solution
A method of digital modulation and direct digital-to-analog conversion that generates multiple sample streams at different phases, which are then converted into continuous analog signals using high-resolution digital-to-analog converters and multiplexed to produce a modulated analog carrier signal, allowing for efficient representation of high-frequency waveforms without the need for integrated analog components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If digital circuit geometry is shrunk to reduce device size and increase processing speed, then device size and cost are reduced and processing speed is increased, but integration of digital and analog circuits becomes more complicated
Solution Approach 1:
The patent divides the high-speed digital signal into multiple lower-speed sample streams at different phases. Each sample stream is processed separately by individual digital-to-analog converters, converting one complex integration problem into multiple simpler parallel processes that can be more easily integrated with analog circuits.
Solution Approach 2:
The patent transforms the time-domain high-speed signal into multiple phase-shifted sample streams, effectively adding a phase dimension to the processing. This allows the system to handle high-frequency waveforms by distributing them across multiple lower-speed channels operating in parallel at different phases.
2Adaptability or versatility
If conventional analog frequency synthesizers and modulation circuits are used for multiple frequency bands, then operation in different countries and frequency bands is enabled, but device size and cost increase
Solution Approach 1:
The patent creates a universal digital processing architecture that can generate modulated analog carrier signals for any frequency band through software or digital configuration, rather than requiring dedicated analog circuits for each band. The system can adapt to different countries and frequency standards by changing digital parameters rather than physical hardware.
3Measurement precision
If high-resolution analog carrier waveforms are generated using conventional methods, then communication quality is maintained, but integration with high-speed digital circuits becomes difficult
Solution Approach 1:
The patent segments the high-resolution analog waveform generation into multiple parallel digital-to-analog conversion channels, each operating at lower speed but maintaining high resolution. This segmentation allows precise digital control while simplifying the analog integration requirements for each individual converter.
Solution Approach 2:
The patent introduces multiple phase-shifted sample streams as intermediary representations between the digital processing domain and the analog output domain. These intermediaries allow the system to maintain high resolution while using simpler, more integratable digital-to-analog converters operating at reduced speeds.
Data Source
AI summary
A modulator described herein provides digital modulation and direct digital-to-analog conversion capable of achieving 12-bit resolution or higher for high frequency signals. The modulator comprises a digital modulator, conversion circuit, and multiplexer. The digital modulator generates a plurality of sample streams at a plurality of different sample phases that collectively represent a desired modulated digital carrier waveform modulated by a digital input signal. The conversion circuit converts the sample streams into a plurality of continuous analog signals. The multiplexer multiplexes the analog signals together to generate a modulated analog carrier signal representative of the desired modulated digital carrier waveform.