Virtual Ground Switching for TDMA Noise Reduction in Portable Terminals
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Portable terminals experience TDMA noise when an earphone is connected, leading to deteriorated call quality and radio receiving performance due to the electrical connection with the real ground, which complicates circuit design.
Innovation Solution
An apparatus and method that utilize a virtual ground to electrically connect the earphone's ground terminal, reducing TDMA noise by switching between a virtual and real ground based on call activation, thereby improving call quality and maintaining radio receiving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ground terminal of the earphone is electrically connected to the real ground of the portable terminal, then the earphone can function properly, but TDMA noise is induced upon the earphone deteriorating call quality
Solution Approach 1:
The patent introduces a virtual ground as an intermediary between the earphone ground terminal and the real ground. The virtual ground acts as a mediator that isolates the earphone from direct electrical connection with the real ground, thereby preventing TDMA noise from being induced upon the earphone while still allowing the earphone to function properly through the audio processing unit.
Solution Approach 2:
The patent segments the ground connection path into separate components: the earphone ground terminal connects to the virtual ground through the audio processing unit, rather than directly connecting to the real ground. This segmentation allows the system to maintain earphone functionality while isolating it from TDMA noise generated by the power amplifier.
2Object-affected harmful factors
If the ground terminal of the interface unit is electrically connected to the virtual ground, then TDMA noise is reduced, but radio receiving performance may be affected
Solution Approach 1:
The patent implements a dynamic ground connection system where the ground terminal of the interface unit can be electrically connected to either the virtual ground or the real ground depending on the operational mode. During call operations, the virtual ground is used to reduce TDMA noise, while during radio receiving operations, the real ground is used to maintain optimal radio receiving performance. This dynamic switching resolves the contradiction between noise reduction and radio receiving performance.
3Reliability
If a separate antenna is included for receiving RF signal, then radio receiving function is improved, but device complexity increases
Solution Approach 1:
The patent makes the earphone serve multiple functions: it acts as both an audio output device for calls and as an antenna for radio receiving operations. By eliminating the need for a separate antenna, the system reduces device complexity while maintaining both calling and radio receiving functions through the multi-functional use of the earphone.
Data Source
AI summary
An apparatus and a method for reducing a time division multiple access noise of a portable terminal. The apparatus includes an interface unit to which an earphone is electrically connected, an audio processing unit including a virtual ground for transmitting and receiving an audio signal through the interface unit, a switch unit located electrically between the interface unit and the audio processing unit for electrically connecting a ground terminal of the interface unit with one of a real ground and the virtual ground of the audio processing unit, and a controller for controlling the switch unit to electrically connect the ground terminal of the interface unit with the virtual ground of the audio processing unit when a call function using the earphone is activated, and to electrically connect the ground terminal of the interface unit with the real ground when the call function using the earphone is deactivated.