Weighted Multi-PWM Audio Output for Higher Bit Resolution
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Solution Overview
Problem
Existing audio output devices using PWM technology have insufficient resolution for high-quality audio data, particularly for 16-bit audio applications, due to limitations in operating clock frequency and carrier frequency, leading to inadequate expression of audio data.
Innovation Solution
The proposed audio output device employs multiple PWM output devices to divide audio data into upper and lower bit parts, with a weighting unit and mixer to synthesize these outputs, allowing for the expression of high-resolution audio even with lower bit resolution PWM devices, by attenuating and combining the outputs to achieve a higher effective bit depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single PWM output device is used with limited operating clock frequency and carrier frequency, then the device complexity is low, but the audio data resolution is insufficient for high-quality audio applications
Solution Approach 1:
The patent divides audio data into multiple bit parts (upper bit part and lower bit part) and processes each part separately through dedicated PWM output devices. This segmentation allows each PWM device to operate at lower frequencies while collectively achieving high-resolution audio output by combining their outputs with appropriate weighting.
2Measurement precision
If multiple PWM output devices are used to divide audio data into upper and lower bit parts, then the audio data resolution is improved, but the device complexity increases
Solution Approach 1:
The patent combines the outputs of multiple PWM output devices through a mixer that synthesizes the weighted PWM signals. By merging the upper bit part output and lower bit part output with appropriate weighting coefficients, the system achieves high-resolution audio output equivalent to processing the full audio data at much higher frequencies.
Data Source
AI summary
An audio output device includes PWM output devices, a weighting unit, a mixer, and an amplifier. The PWM output devices divide audio data into multiple parts including an upper bit part to a lower bit part, and output the multiple parts of the audio data as PWM outputs. The weighting unit weights the PWM outputs from the PWM output devices. The mixer synthesizes the PWM outputs after being weighted. The amplifier supplies an electric current to a sounding body in accordance with a synthesis result by the mixer to cause the sounding body to emit a sound.