Transmitter Modulation and Amplification Control
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Solution Overview
Problem
Existing radio transmitters face challenges in accurately selecting modulation schemes and amplification levels, leading to distortion and spectral issues at high gain levels, particularly when using high data rate modulation schemes, which can result in unreliable signal decoding and power inefficiency.
Innovation Solution
A transmitter system with a control unit that interdependently selects modulation schemes and amplification levels, using a combination of pre-amplifiers and power amplifiers, and operates in restricted modes to avoid high gain distortions, allowing for fallback to lower power or simpler modulation schemes when necessary, ensuring reliable signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a standard power amplifier is used to increase transmitted power level, then the transmission range is improved, but signal distortion occurs causing spectral distortion and loss of data integrity
Solution Approach 1:
The system dynamically switches between different modulation schemes based on the operating conditions and amplifier gain level. When the power amplifier is activated to increase transmitted power, the control unit automatically selects a more robust modulation scheme that can tolerate the amplifier's non-linearity, thus maintaining data transmission reliability while achieving extended transmission range.
Solution Approach 2:
The invention changes the modulation scheme parameter in response to changes in amplifier gain level. When transitioning from low gain (pre-amplifier only) to high gain (power amplifier activated), the system adjusts the modulation scheme from higher-order modulations to more robust modulations, optimizing the balance between data rate and reliability under different power conditions.
2Reliability
If a more linear amplifier is used to reduce distortion, then signal quality is improved, but cost and circuit board area increase
Solution Approach 1:
Instead of using an expensive high-linearity power amplifier, the invention employs a standard, lower-cost power amplifier with acceptable linearity. The system compensates for the amplifier's limitations through intelligent modulation scheme selection, achieving comparable overall performance while reducing hardware cost and complexity.
Solution Approach 2:
The control unit acts as an intermediary that mediates between the amplifier's limitations and the modulation scheme selection. By introducing this control layer, the system can use a simpler amplifier while maintaining signal quality through adaptive modulation, avoiding the need for expensive high-linearity amplifiers.
3Productivity
If a higher data rate modulation scheme is used, then productivity is improved, but the system becomes more sensitive to amplifier non-linearity and interference
Solution Approach 1:
The system dynamically adapts the modulation scheme based on the amplifier configuration and channel conditions. When operating with the pre-amplifier only (lower gain), the system can use higher data rate modulation schemes. When the power amplifier is activated (higher gain), the system automatically switches to more robust modulation schemes that are less sensitive to non-linearity and interference, thus maintaining productivity while managing sensitivity.
Solution Approach 2:
The invention changes the modulation scheme parameter in response to changes in amplifier gain level and channel conditions. This parameter adaptation allows the system to optimize the trade-off between data rate and robustness, selecting higher-order modulations when conditions permit and switching to more robust modulations when amplifier non-linearity or interference becomes significant.
Data Source
AI summary
A transmitter for transmitting signals, comprising: a modulator for modulating a data signal, the modulator being capable of modulating the data signal according to any of two or more modulation schemes to form a modulated signal; an amplification arrangement for amplifying the modulated signal with any of two or more levels of gain; and a control system configured to interdependently select one of the modulation schemes and one of the levels of gain, and to control the modulator to adopt the selected modulation scheme and to control the amplifier to adopt the selected level of gain.