RF Differential Converter Gain Control Against Disturbing Waves
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Solution Overview
Problem
Existing wireless communication circuits for digital TV broadcasting struggle to maintain optimal signal quality in strong electric fields due to interference from disturbing waves, leading to a degradation in the carrier-to-noise (C/N) value of intermediate frequency (IF) signals.
Innovation Solution
A wireless communication circuit with a low noise amplifier, first and second gain control amplifiers, a differential converter, mixer circuit, filter, and control circuits that dynamically adjust gains and reference levels based on signal levels to reduce the impact of disturbing waves, improving the C/N value by optimizing noise figure (NF) and distortion characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the gain of the amplifier is reduced under strong electric field conditions to reduce disturbing wave influence, then the harmful effect of disturbing waves is reduced, but the signal level of the desired signal is also reduced
Solution Approach 1:
The patent implements dynamic gain control by switching between a first gain (higher) and a second gain (lower) based on the detected signal level. When the signal level exceeds a threshold indicating strong electric field conditions, the system switches to the lower second gain to reduce disturbing wave influence while maintaining adequate signal level through coordinated adjustment of subsequent amplifier stages.
Solution Approach 2:
The system changes the gain parameter of the amplifier dynamically based on signal level detection. The control circuit monitors the signal level and switches between different gain states (first gain and second gain) to optimize the balance between reducing disturbing wave influence and maintaining sufficient signal level for reliable reception.
2Reliability
If the gain of the amplifier is increased to maintain signal level in weak electric field areas, then the signal level is improved, but the harmful effect of disturbing waves increases
Solution Approach 1:
The system dynamically adjusts the amplifier gain based on the detected signal level. In weak electric field conditions where the signal level is below the threshold, the system uses the higher first gain to ensure adequate signal level while the lower signal level naturally limits the amplification of disturbing waves.
Solution Approach 2:
The gain parameter is changed based on signal level conditions. When the signal level is low (weak electric field), the system switches to the higher first gain to maintain reliable signal reception. The coordinated control of multiple amplifier stages ensures that disturbing waves are not excessively amplified even when using higher gain.
3Device complexity
If a fixed gain amplifier is used, then the device complexity is reduced, but the adaptability to different electric field conditions deteriorates
Solution Approach 1:
The patent implements a dynamic gain control system that switches between a first gain and a second gain based on detected signal level. This dynamic adaptation allows the amplifier to optimize performance across different electric field conditions (weak and strong fields) while maintaining a relatively simple control structure that only requires gain switching and coordinated adjustment of subsequent stages.
Data Source
AI summary
A wireless communication circuit has a second control circuit which reduces the gain of the differential converter when the signal level of the RF signal is at least a specified level and the RF signal includes a disturbing wave of a predetermined level or higher.