Variable Transformer Feedback for Vehicle Intermodulation Noise
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Solution Overview
Problem
Vehicles face challenges in attenuating intermodulation noise, which distorts audio and video broadcasts due to radio signals of different frequencies, and existing bandpass filters are ineffective in blocking this noise.
Innovation Solution
A vehicle system comprising an antenna, amplifier, detector, variable transformer, and auto gain control, where a controller adjusts the conversion ratio of the variable transformer and activates/deactivates auto gain control based on the output signal magnitude to prevent signal saturation and reduce intermodulation noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a bandpass filter is used to block radio signals of different frequencies, then interference from other frequencies is reduced, but intermodulation noise cannot be effectively blocked
Solution Approach 1:
The patent employs a variable transformer with dynamically adjustable conversion ratio instead of a fixed bandpass filter. The controller adjusts the conversion ratio in real-time based on the detected output signal characteristics, enabling the system to adaptively respond to varying intermodulation conditions and effectively block noise that static filters cannot handle
Solution Approach 2:
The system implements a feedback mechanism where the detector monitors the output signal of the amplifier and feeds this information back to the controller. The controller then adjusts the variable transformer's conversion ratio based on this feedback, creating a closed-loop system that continuously optimizes noise suppression while maintaining signal quality
2Power
If the gain of the amplifier is increased to amplify weak broadcast signals, then signal strength is improved, but the output signal becomes saturated and intermodulation noise increases
Solution Approach 1:
The variable transformer provides dynamic gain control by adjusting its conversion ratio based on real-time signal conditions. When the broadcast signal is weak, the transformer provides higher gain amplification; when the signal strengthens or intermodulation occurs, the conversion ratio is adjusted to reduce gain, preventing saturation and noise generation
Solution Approach 2:
The system changes the operational parameters of the amplifier chain by adjusting the conversion ratio of the variable transformer. This parameter adjustment allows the system to optimize the balance between signal amplification and noise suppression, adapting to varying input signal strengths and interference conditions
3Device complexity
If a fixed conversion ratio transformer is used in the feedback path, then the circuit structure is simple, but the system cannot adapt to varying signal conditions and effectively suppress intermodulation
Solution Approach 1:
The patent replaces a fixed conversion ratio transformer with a variable transformer whose conversion ratio can be dynamically adjusted by the controller. This dynamic capability enables the system to adapt to varying signal conditions, interference levels, and operating environments while maintaining relatively simple circuit architecture
Solution Approach 2:
The variable transformer serves multiple functions: it provides feedback signal transformation, enables adaptive gain control, and suppresses intermodulation noise. By making the conversion ratio adjustable, a single component performs what would otherwise require multiple fixed components, reducing overall system complexity while enhancing adaptability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively attenuates noise while maintaining a high signal-to-noise ratio by dynamically controlling the gain and conversion ratio of the amplifier, reducing intermodulation distortion in broadcast signals.
Implementation Method 1
a variable transformer configured to output a negative feedback signal based on the detected output signal
Implementation Method 2
an amplifier configured to amplify the broadcast signal
Data Source
AI summary
A vehicle includes an antenna configured to receive a broadcast signal, an amplifier configured to amplify the broadcast signal, a detector configured to detect an output signal of the amplifier, a variable transformer configured to output a negative feedback signal based on the detected output signal, an auto gain control configured to control an input signal of the amplifier based on the negative feedback signal and a controller configured to control the variable transformer and the auto gain control based on the output signal of the amplifier.