Abstract: Systems and methods are provided for a level shifter. A level shifter includes a network of transistors configured to receive a signal at a first node in a first voltage domain and to generate a corresponding signal at a second node in a second voltage domain during a transition period of time. A self timing circuit is configured to receive an initiation signal based on the signal at the first node and to generate a voltage transition accelerator signal that is used to pull up the second node prior to the expiration of the transition period of time.

Abstract: A handheld electronic device is provided. The handheld electronic device includes a housing, a first speaker, a second speaker, a third speaker, and a fourth speaker. The housing includes a back plate, a first sidewall, and a second sidewall. The first sidewall and the second sidewall are disposed at opposite sides of the back plate. The first sidewall is parallel to the second sidewall, and a length of the first sidewall is greater than a distance between the first sidewall and the second sidewall. The first speaker and the second speaker are disposed in the housing and arranged along the first sidewall. The third speaker and the fourth speaker are disposed in the housing and arranged along the second sidewall.

Abstract: A sound quality evaluation method and a sound quality evaluation system using same are provided. The sound quality evaluation system records playback of a test audio file on a plurality of playback devices to generate a plurality of pieces of audio data, and divides the audio data into a plurality of frequency bands. The sound quality evaluation system calculates the frequency bands to obtain a plurality of evaluation scores of the playback devices. The sound quality evaluation system captures sound quality ranking information corresponding to the playback devices from a reference source, and adjusts the evaluation scores according to the sound quality ranking information, to further obtain a reference model. The sound quality evaluation system adjusts correspondingly evaluation scores of a plurality of to-be-tested playback devices according to the reference model, to obtain sound quality ranking information of the to-be-tested playback devices.

Abstract: A sound quality evaluation method and a sound quality evaluation system using same are provided. The sound quality evaluation system records playback of a test audio file on a plurality of playback devices to generate a plurality of pieces of audio data, and divides the audio data into a plurality of frequency bands. The sound quality evaluation system calculates the frequency bands to obtain a plurality of evaluation scores of the playback devices. The sound quality evaluation system captures sound quality ranking information corresponding to the playback devices from a reference source, and adjusts the evaluation scores according to the sound quality ranking information, to further obtain a reference model. The sound quality evaluation system adjusts correspondingly evaluation scores of a plurality of to-be-tested playback devices according to the reference model, to obtain sound quality ranking information of the to-be-tested playback devices.

Abstract: A handheld electronic device includes a first speaker, a second speaker, and an audio controller. The audio controller includes a signal receiving unit, a frequency crossover unit, a harmonic-wave generating unit, a low frequency enhancement unit, and a signal synthesis unit. The signal receiving unit receives an original sound signal and generates a first channel signal and a second channel signal according to the original sound signal. The frequency crossover unit sets a preset frequency crossover point to filter the first channel signal to generate a low frequency signal. The harmonic-wave generating unit generates harmonic waves according to the low frequency signal. The low frequency enhancement unit generates an enhancing low-frequency signal according to the harmonic waves. The signal synthesis unit generates a first channel enhanced signal according to the enhancing low-frequency signal and drives the first speaker.

Abstract: A handheld electronic device includes a first speaker, a second speaker, and an audio controller. The audio controller includes a signal receiving unit, a frequency crossover unit, a harmonic-wave generating unit, a low frequency enhancement unit, and a signal synthesis unit. The signal receiving unit receives an original sound signal and generates a first channel signal and a second channel signal according to the original sound signal. The frequency crossover unit sets a preset frequency crossover point to filter the first channel signal to generate a low frequency signal. The harmonic-wave generating unit generates harmonic waves according to the low frequency signal. The low frequency enhancement unit generates an enhancing low-frequency signal according to the harmonic waves. The signal synthesis unit generates a first channel enhanced signal according to the enhancing low-frequency signal and drives the first speaker.

Abstract: An audio processing method includes the following steps: receiving audio information; capturing a square wave signal, a white signal, and a speech signal of the audio information; calculating a loudness value of the audio information; calculating a first sound quality value and a second sound quality value of the audio information by using the square wave signal, the white signal, and the speech signal of the audio information; calculating a sound quality level of the audio information by using a first calculation formula, the first calculation formula being the loudness value*[1+(B*the first sound quality value+C*the second sound quality value)], where B and C are respectively values greater than 0 and less than 0.1; and displaying a value of the sound quality level of the audio information.

Abstract: An audio processing method includes the following steps: receiving audio information; capturing a square wave signal, a white signal, and a speech signal of the audio information; calculating a loudness value of the audio information; calculating a first sound quality value and a second sound quality value of the audio information by using the square wave signal, the white signal, and the speech signal of the audio information; calculating a sound quality level of the audio information by using a first calculation formula, the first calculation formula being the loudness value*[1+(B*the first sound quality value+C*the second sound quality value)], where B and C are respectively values greater than 0 and less than 0.1; and displaying a value of the sound quality level of the audio information.