Cellular Antenna Impedance Control for FM Interference Mitigation
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Solution Overview
Problem
Impedance changes in cellular communication subsystems of portable devices can cause interference and unwanted audio ticks during FM communication signal reception and transmission, as the FM antenna is affected by the impedance changes of the cellular antennas, making it challenging to maintain clear audio signals.
Innovation Solution
A method and device that utilize two electronic processors to detect audio signal events and generate an alert signal, causing the cellular communication subsystem to set substantially constant impedances for its antennas, thereby mitigating interference between the cellular and FM communication subsystems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If spatial antenna isolation is increased to prevent impedance changes, then interference between cellular and FM subsystems is reduced, but mechanical constraints make this impractical
Solution Approach 1:
The patent changes the impedance parameter of cellular antennas from variable to substantially constant during FM operations. The processor detects FM signal reception and controls the antenna tuner to maintain constant impedance, preventing the impedance changes that cause interference with FM audio signals.
Solution Approach 2:
The system performs preliminary detection of FM signal reception status and proactively adjusts cellular antenna impedance before interference occurs. The processor monitors for FM signals and pre-emptively sets the antenna impedance to a constant value that prevents interference with FM operations.
2Reliability
If cellular antenna impedance is kept constant during FM operations, then audio signal quality is improved, but cellular communication functionality may be restricted
Solution Approach 1:
The system dynamically adjusts antenna impedance based on operational mode. During FM signal reception, the impedance is held constant to ensure audio quality. When cellular operations resume, the system transitions back to dynamic impedance adjustment for optimal cellular communication performance.
Solution Approach 2:
The system periodically monitors for FM signal reception and alternates between constant impedance mode (during FM reception) and dynamic impedance adjustment mode (during cellular operations). This periodic switching ensures both FM audio quality and cellular communication functionality are maintained at appropriate times.
Data Source
AI summary
Portable communication device and method for mitigating interference. One example portable communication device includes a frequency-modulated (FM) communication subsystem, a cellular communication subsystem, a first electronic processor, and a second electronic processor. The FM communication subsystem includes an FM modem and at least one FM antenna. The cellular communication subsystem includes a plurality of cellular antennas, a plurality of antenna tuners, and a cellular modem. The first electronic processor is configured to generate an alert signal responsive to detecting one of an audio signal reception by the FM communication subsystem and an audio signal transmission by the FM communication subsystem. The second electronic processor is configured to receive the alert signal from the first electronic processor. The second electronic processor is also configured to responsively cause the cellular communication subsystem to set substantially constant impedances for the plurality of cellular antennas.