Delta-Sigma Digital Transmitter Architecture for Efficient RF Output
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Solution Overview
Problem
Traditional transmitter architectures face inefficiencies due to the use of linear power amplifiers in back-off, which results in poor power efficiency and stringent linearity constraints, especially when handling complex modulation techniques for multi-standard communication standards.
Innovation Solution
A digital transmitter architecture utilizing low-frequency Delta-Sigma Modulators (DSMs) cascaded with a binary up-sampler and modulator block, operating at higher frequencies, to transform envelope and phase modulated signals into binary stream signals, allowing for efficient power amplification and improved signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If linear power amplifiers are used in back-off mode, then linearity is improved, but power efficiency deteriorates
Solution Approach 1:
The patent replaces the traditional linear power amplifier with a digital transmitter architecture using Delta-Sigma Modulators and switching power amplifiers. This substitution of the amplification mechanism allows efficient switching operation while maintaining signal fidelity through digital modulation techniques, thereby improving power efficiency without sacrificing linearity.
Solution Approach 2:
The invention changes the operating parameters by using switching power amplifiers operated in saturation mode rather than linear amplifiers in back-off mode. Combined with Delta-Sigma modulation and noise shaping, this parameter change enables the system to achieve both high efficiency and acceptable linearity performance.
2Adaptability or versatility
If multiple transmitters are dedicated to different communication standards, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal digital transmitter architecture that can operate with multiple communication standards through software configuration and parameter adjustment. The core Delta-Sigma modulator and up-sampler blocks remain the same, while standard-specific adjustments are made through digital signal processing, allowing one transmitter to serve multiple functions.
Solution Approach 2:
The invention introduces dynamic reconfigurability to the transmitter architecture, allowing it to adapt its parameters and characteristics based on the required communication standard. This dynamic adjustment capability enables a single transmitter to handle multiple standards without requiring separate dedicated hardware for each standard.
3Use of energy by moving object
If Delta-Sigma Modulators operate at low frequency, then power efficiency is improved, but output frequency is insufficient for RF applications
Solution Approach 1:
The patent divides the frequency multiplication function into separate stages: the Delta-Sigma Modulator operates at low frequency for efficiency, followed by a dedicated up-sampler block that incrementally increases the frequency. This segmentation allows each component to operate in its optimal frequency range, maintaining power efficiency while achieving the required RF output frequency.
Solution Approach 2:
The invention performs preliminary signal processing and modulation at low frequencies using the Delta-Sigma Modulator, then applies frequency up-sampling as a subsequent stage. This preliminary action at low frequency reduces the computational and power burden, with the final high-frequency signal generated through efficient up-sampling rather than direct high-frequency modulation.
Data Source
AI summary
The present disclosure is concerned with a digital transmitter using Delta-Sigma modulators (DMSs) that uses an up-sampler and modulator block that follows the DSMs to generate the RF equivalent of the baseband signal to be transmitted. The up-sampler and modulator block is simple to implement and contains only one or a few multiplexers implemented in high speed logic technology.