Remote Active Antenna Gain Control via Feedback Loop
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Solution Overview
Problem
Conventional mobile satellite radio receiver systems face challenges in maintaining optimal gain adjustment due to varying RF signal strengths, leading to potential overloading and bit errors, especially when near terrestrial repeaters, and struggle to achieve linearity across a wide range of gains.
Innovation Solution
A system that generates a control signal indicative of RF signal strength to adjust the gain of the low noise amplifier in the active antenna, using a feedback loop to regulate the RF amplification gain and prevent overloading, while allowing for improved linearity and reduced third-order input intercept point requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the amplifier has a fixed high gain to optimize weak signal reception, then weak signal reception is improved, but the system becomes prone to overloading when strong signals are received
Solution Approach 1:
The patent applies dynamics by making the amplifier gain adjustable rather than fixed. The system dynamically changes the amplifier gain based on the received signal strength, using a control circuit that monitors signal levels and adjusts the gain accordingly. This allows the system to optimize for weak signals when needed while preventing overload when strong signals are present, resolving the contradiction between weak signal reception and overloading prevention.
2Reliability
If the RF tuner gain is adjusted according to signal strength, then overloading is prevented, but linearity becomes difficult to achieve over a wide gain range
Solution Approach 1:
The patent applies preliminary action by adjusting the amplifier gain before the signal reaches the RF tuner. The control circuit proactively regulates the signal level at the amplifier output, preventing the RF tuner from receiving signals that would cause overload or nonlinearity. This preliminary gain control protects the RF tuner from operating in nonlinear regions, maintaining linearity across wide signal strength variations.
3Power
If the system operates near a terrestrial repeater with strong signals, then signal strength is improved, but bit errors occur due to tuner overloading
Solution Approach 1:
The patent applies feedback by implementing a control circuit that monitors the received signal strength and uses this information to adjust the amplifier gain. When strong signals from terrestrial repeaters are detected, the control circuit reduces the amplifier gain to prevent tuner overload and bit errors. This closed-loop feedback mechanism ensures that the system maintains optimal operating conditions regardless of external signal strength variations.
Data Source
AI summary
A receiver includes a tuner and a circuit. The tuner receives an indication of a radio frequency signal from an antenna feedline in response to the radio frequency signal being provided to the antenna feedline by an amplifier. The circuit transmits a control signal to the antenna feedline to control a gain of the amplifier in response to a strength of the radio frequency signal.