Digital Audio Driver Edge Control for RF Interference Reduction
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Solution Overview
Problem
Personal mobile devices experience signal interference due to frequency harmonics from digital signals, which can lead to undesirable operation, particularly affecting radio-frequency signals.
Innovation Solution
A digital microphone integrated circuit (IC) with a driver module that controls the edge rate, edge decision, and amplitude of digital audio output signals based on the frequency of radio-frequency signals to minimize interference, maintaining the selected clock rate and reducing spectral content overlap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If digital signals are driven over relatively long distances on a digital bus, then digital signal transmission is achieved, but frequency harmonics cause signal interference with radio-frequency signals
Solution Approach 1:
The patent applies dynamics by making the digital signal characteristics adjustable rather than fixed. The system dynamically modifies edge rates and timing of digital signals based on detected radio-frequency signal conditions, allowing the digital bus to operate at longer distances without causing harmful frequency harmonics interference to RF signals.
Solution Approach 2:
The patent changes physical parameters of the digital signal, specifically edge rates and timing characteristics. By adjusting these parameters, the system reduces the generation of frequency harmonics that would otherwise interfere with radio-frequency signals, enabling stable operation over longer digital bus distances.
2Productivity
If edge rate of digital signals is increased for faster data transmission, then productivity is improved, but spectral content overlaps with radio-frequency signals causing interference
Solution Approach 1:
The system dynamically adjusts the edge rate of digital signals based on the detected radio-frequency signal environment. When RF signals are present, the edge rate is modified to avoid spectral overlap, while maintaining high data transmission rates when RF interference is minimal or absent.
Solution Approach 2:
The patent modifies the edge rate parameter of digital signals to control their spectral content. By carefully selecting and adjusting this parameter, the system achieves high productivity through fast edge rates while avoiding spectral overlap with radio-frequency signals that would cause interference.
3Speed
If clock frequency is increased for faster processing, then speed is improved, but signal interference with radio-frequency signals increases
Solution Approach 1:
The patent adjusts the clock frequency parameter to optimize processing speed while minimizing radio-frequency interference. The system modifies clock frequency characteristics to avoid generating harmful harmonics that would interfere with RF signals, thereby maintaining high processing speed without compromising RF signal integrity.
Data Source
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AI summary
A mobile device may include a digital data driver and digital data receiver for communication of digital signals within the mobile device at a selected clock rate. The mobile device may also have a device external for the digital data driver and digital data receiver for communication of external signals, such as radio-frequency signals, to and from the mobile device. To avoid interference of frequency harmonics of a digital signal with such external signals, the digital data driver may be configured to control the digital signal based on the frequency of the external signals, such that interference of the external signal by spectral content of the digital signal is minimized, while maintaining the selected clock rate.