Audio Receiver Noise Cancellation via Dynamic Impedance Switching
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Solution Overview
Problem
Current technologies fail to effectively cancel or reduce current noise in audio transmission signals when an audio source device is charged through a power supply, which degrades audio quality.
Innovation Solution
An audio receiver with a noise cancelling circuit and a switch circuit is used to dynamically adjust impedance states based on whether the audio source device is being charged, preventing voltage dissipation to ground and thus reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the audio receiver outputs power supply current to charge the audio source device through the power supply line, then the audio source device can be charged, but current noise is generated in the audio transmission signal path affecting audio quality
Solution Approach 1:
The patent segments the ground connection path by introducing a switch circuit that can independently control the connection between the second signal port and power ground port. This segmentation allows the audio ground line to remain isolated from power ground during charging, preventing current noise from contaminating the audio signal path while maintaining charging functionality.
Solution Approach 2:
The patent implements dynamic impedance control through the switch circuit, which changes the connection state between the second signal port and power ground port based on charging status. During charging, the switch maintains high impedance to block noise; during non-charging, it switches to low impedance for proper grounding. This dynamic adaptation resolves the contradiction between charging and noise prevention.
2Reliability
If the connection state between the second signal port and power ground port is maintained at low impedance, then the voltage level of the second signal port can dissipate to ground level, but current noise appears in the audio transmission signal path when charging
Solution Approach 1:
The switch circuit dynamically adjusts the impedance state between the second signal port and power ground port based on real-time detection of charging status. When charging is detected, the switch transitions to high impedance state to prevent noise coupling. When no charging is detected, it transitions to low impedance state for proper voltage reference. This dynamic switching resolves the contradiction between voltage stabilization and noise prevention.
Solution Approach 2:
The patent employs a detection circuit that monitors the charging status and provides feedback to control the switch circuit. This feedback mechanism enables the system to automatically adjust the connection state based on actual operating conditions, ensuring voltage stabilization when needed while preventing noise coupling during charging operations.
3Object-affected harmful factors
If the connection state between the second signal port and power ground port is set to high impedance state during charging, then current noise is prevented, but the voltage level of the second signal port cannot dissipate to ground level
Solution Approach 1:
The patent segments the grounding function by separating the audio ground line (second signal port) from the power ground line through the switch circuit. During charging, the audio ground line is isolated from power ground to prevent noise, while maintaining its own reference stability. This segmentation allows noise prevention without sacrificing voltage reference integrity.
Solution Approach 2:
The switch circuit provides dynamic impedance control that adapts to different operating modes. During charging, it maintains high impedance to prevent noise while the audio ground line maintains its reference through other means. During non-charging, it switches to low impedance for proper grounding. This dynamic behavior resolves the contradiction between noise prevention and voltage reference stability.
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 solution effectively cancels current noise by maintaining a high impedance state when charging and switching to a low impedance state when not charging, ensuring clear audio signals without noise interference.
Implementation Method 1
when the audio receiver (100) is outputting a power supply current to the audio source device (101) through the power supply port (PS1) via the power supply line (VDD), a connection state between the second signal port (S2) and the power ground port (G1) is at a high impedance state
Data Source
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AI summary
An audio receiver (100) includes a first signal port (S1), a second signal port (S2), a power supply port (PS1), a power ground port (G1), and an amplifier circuit (105). The first signal port (S1) is coupled to an audio signal line (Dn, Dp) of a transmission interface. The power supply port (PS1) is coupled to a power supply line (VDD) of the transmission interface to generate a power supply level to the power supply line (VDD). The power ground port (G1) is connected to the ground level and to a power ground line (GND) of the transmission interface. When the audio receiver (100) is outputting a power supply current to the audio source device (101) through the power supply port (PS1) via the power supply line (VDD), a connection state between the second signal port (S2) and the power ground port (G1) is at a high impedance state.