Digital Vector Modulator Without DAC-Based Gain Control
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Solution Overview
Problem
Conventional vector signal modulators require digital-to-analog converters (DACs) to control variable gain amplifiers, increasing complexity and production costs due to the need for analog signal control.
Innovation Solution
A digital-controlled vector signal modulator that uses a switching circuit with digital bits to directly adjust in-phase and quadrature signals without the need for DACs, simplifying the design and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If variable gain amplifiers (VGAs) are used to adjust in-phase and quadrature signals, then signal amplitude control is improved, but device complexity increases due to the requirement of digital-to-analog converters (DACs)
Solution Approach 1:
The patent extracts and removes the DAC component from the traditional VGA-based modulator architecture. Instead of using analog voltage control signals that require DAC conversion, the invention directly uses digital control signals to adjust the gain of VGAs, thereby eliminating the DAC and its associated complexity while maintaining amplitude control precision
Solution Approach 2:
The patent substitutes the analog control mechanism (voltage control requiring DAC) with a digital control mechanism. Digital control signals directly regulate the VGA gain through digital control interfaces, replacing the mechanical/analog signal conversion pathway and reducing overall system complexity
2Adaptability or versatility
If digital-to-analog converters (DACs) are used to control variable gain amplifiers, then gain adjustment capability is improved, but production cost increases
Solution Approach 1:
The patent removes the DAC component from the signal path, thereby reducing bill of materials cost and simplifying the manufacturing process. The gain adjustment capability is maintained through direct digital control of VGAs, eliminating the need for expensive DAC hardware while preserving adaptability
Solution Approach 2:
The patent replaces the expensive DAC component with a more cost-effective digital control implementation. By using digital control signals that can be generated and processed by standard digital logic circuits or microcontrollers, the system achieves similar functionality at lower production cost
Data Source
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AI summary
A vector modulator includes a quadrature component generator (12), configured to generate an input in-phase signal (Ii) and an input quadrature signal (Qi) according to an input radio frequency (RF) signal (RFin); a switching circuit (14), receiving a plurality of bits (B1,...,BN), comprising a plurality of switches controlled by the plurality of bits, configured to generate an output in-phase signal (Io) and an output quadrature signal (Qo) according to the plurality of bits (B1,...,BN), where the output in-phase signal (Io) and the output quadrature signal (Qo) are related to input in-phase signal (Ii) and the input quadrature signal (Qi); and a combining module (16), configured to generate an output RF signal (RFout) according to the output in-phase signal (Io) and the output quadrature signal (Qo).