Balanced Analog Receiver Circuit for Ground Loop Noise Rejection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing audio signal receivers face challenges in effectively eliminating ground noise from single-ended analog signals due to ground loops, which can introduce noise and interference, especially when devices share a common ground, and conventional solutions like differential amplifiers can introduce additional noise.
Innovation Solution
A single-ended analog signal receiver apparatus is designed with a buffer gain unit and a post-stage balance circuit unit, utilizing a series-connected bias resistor to create a floating ground signal that is buffered and amplified, allowing for common mode rejection to eliminate noise, while maintaining balanced input impedance and electromagnetic compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a ground lift is added to eliminate ground loop noise, then common mode noise is reduced, but high-impedance components add noise and the floating source becomes noisy
Solution Approach 1:
The patent introduces a buffer gain unit as an intermediary component between the ground lift and the differential amplifying circuit. This buffer unit with controlled gain absorbs the high-impedance characteristics while providing a low-impedance output to the differential stage, thereby maintaining noise rejection capabilities without introducing excessive noise from high-impedance components.
Solution Approach 2:
The patent changes the impedance parameter by using a buffer gain unit that transforms the high-impedance floating ground connection into a low-impedance signal source for the differential amplifying circuit. This parameter transformation allows the system to benefit from ground lift noise rejection while avoiding the noise penalties associated with high-impedance components.
2Object-affected harmful factors
If a differential amplifying circuit is used for common mode rejection, then ground noise is eliminated, but the circuit complexity increases and additional noise may be introduced
Solution Approach 1:
The patent applies preliminary action by using the buffer gain unit to pre-process and condition the floating ground signal before it enters the differential amplifying circuit. This preliminary buffering and gain adjustment simplifies the requirements for the differential stage, allowing for a more straightforward circuit design that achieves common mode rejection without excessive complexity.
3Object-affected harmful factors
If a floating ground is set to convert current noise into voltage noise, then common mode rejection can be implemented, but the circuit becomes susceptible to interference between ungrounded devices
Solution Approach 1:
The buffer gain unit serves as an intermediary that isolates the floating ground conversion from the differential amplifying circuit. This intermediary stage provides controlled impedance and buffering that reduces the susceptibility to interference between ungrounded devices while maintaining the ability to convert and reject common mode noise effectively.
Data Source
AI summary
A single-ended analog signal receiver apparatus is provided, which can cope with an external ground current and an undefined impedance through an AC bootstrap input impedance, while considering electromagnetic compatibility, convert a received single-ended analog signal into a balanced output differential signal, and may provide at a post-stage circuit output an output signal with lower noise through common mode rejection.