Variable Gain Amplifier AGC Circuit for Wireless Receiver
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Solution Overview
Problem
Existing wireless communication receivers face challenges in maintaining a consistent output signal amplitude and signal-to-noise ratio (SNR) due to varying input signal strengths, which requires adaptive gain control to optimize sensitivity and power consumption while managing non-linear noise figures.
Innovation Solution
The implementation of a receiver system with multiple variable gain amplifiers and an automatic gain control (AGC) circuit that adjusts the gain ratio between different frequency bands to maintain a target range, using fine unit steps to control total gain and minimize non-linear noise figure changes, thereby optimizing power consumption and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single variable gain amplifier is used to control total gain, then the output signal amplitude can be maintained, but the noise figure becomes non-linear and power consumption increases
Solution Approach 1:
The patent divides the single variable gain amplifier into multiple variable gain amplifiers, each operating at different frequency bands (first frequency band and second frequency band). By segmenting the gain control function across multiple amplifiers with different characteristics, the system can maintain linear noise figure while achieving the required output signal amplitude consistency.
Solution Approach 2:
Each variable gain amplifier is assigned specific operational characteristics suited to its frequency band. The first variable gain amplifier handles the first frequency band with specific gain characteristics, while the second variable gain amplifier handles the second frequency band with different characteristics. This local optimization of quality parameters allows the overall system to maintain linearity and reduce noise figure while achieving consistent output.
2Reliability
If gain is increased to improve sensitivity, then signal reception improves, but power consumption increases
Solution Approach 1:
The patent implements dynamic gain control by adjusting the gain of variable gain amplifiers based on the strength of the received signal. The automatic gain control circuit continuously monitors signal strength and dynamically adjusts the gain parameters of the amplifiers to maintain optimal sensitivity while minimizing power consumption. This dynamic adaptation allows the system to achieve high sensitivity only when needed, reducing overall power consumption.
Solution Approach 2:
The system changes the operational parameters (gain values) of the variable gain amplifiers based on signal conditions. By varying the gain parameters dynamically according to received signal strength, the system optimizes the balance between sensitivity and power consumption, achieving high sensitivity during weak signal conditions while reducing power consumption during strong signal conditions.
3Object-generated harmful factors
If multiple variable gain amplifiers are used with different frequency bands, then noise figure linearity is maintained, but device complexity increases
Solution Approach 1:
The patent designs the multiple variable gain amplifiers to work together as an integrated system where each amplifier handles a specific frequency band but contributes to the overall gain control function. The automatic gain control circuit coordinates both amplifiers, allowing them to function as a unified system that maintains noise figure linearity while managing complexity through coordinated multi-functional operation.
Data Source
AI summary
Provided is a receiver configured to perform automatic gain control (AGC), the receiver including a first variable gain amplifier configured to amplify, according to a first variable gain, a signal of a first frequency band, a second variable gain amplifier configured to amplify, according to a second variable gain, a signal of a second frequency band generated by frequency converting the amplified signal of the first frequency band, and an AGC circuit configured to control a total gain by controlling a gain ratio between the first variable gain and the second variable gain to be within a set target range by adjusting at least one of the first variable gain and the second variable gain.