Multi-Path RF Transmitter for Low-Power Distortion Control
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Solution Overview
Problem
Existing low power transmitters in sensor networks face inefficiencies in power consumption and signal distortion due to the inclusion of unnecessary components like output amplifiers and drivers, especially at low power levels, which are not needed for effective RF signal transmission.
Innovation Solution
A transmitter design with multiple signal paths, each having different gain and frequency, allowing selective activation or deactivation based on application needs, minimizing power consumption by powering down unused paths and optimizing component usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If output amplifier and driver are included in the RF signal chain to support maximum dynamic range at highest output RF signal amplitude, then the transmitter can provide desired resolution at highest output RF signal amplitude, but unnecessary power consumption occurs at low amplitudes and unnecessary signal distortion is added to low power RF output signal
Solution Approach 1:
The transmitter is divided into multiple independent signal paths (first signal path with full RF chain including output amplifier and driver, second signal path with simplified baseband-to-RF conversion without output amplifier and driver). Each path can be independently activated or deactivated based on the required output power level, allowing the system to segment the RF signal chain operations to avoid unnecessary power consumption at low amplitudes while maintaining high resolution capability when needed.
2Power
If output amplifier and driver are activated to scale baseband signal and RF signal amplitude, then maximum dynamic range is achieved, but signal distortion increases at low power levels
Solution Approach 1:
The transmitter dynamically selects between different signal paths based on the required output power level. At low power levels, the second signal path is activated which bypasses the output amplifier and driver stages that cause distortion. At high power levels, the first signal path is activated which includes the full RF chain with output amplifier and driver to achieve maximum dynamic range. This dynamic path selection eliminates signal distortion at low power levels while maintaining high power capability when needed.
Data Source
Figure 1A
Figure 1B~1C
Figure 2
AI summary
An apparatus includes multiple signal paths for signal transmission, and control circuitry. The multiple signal paths include a first signal path and a second signal path. The first signal path is configured to convert a digital baseband signal to a first radio frequency (RF) signal having a first frequency and a first gain. The second signal path is configured to convert a digital baseband signal to a second RF signal having a second frequency and a second gain, wherein the second gain is less than the first gain. The control circuitry is coupled to the plurality of signal paths and is configured to receive one or more control signals to enable selective activation of at least one signal path of the plurality of signal paths.