NTU Amps Up Mobile Sound Quality

Singapore, April 26, 2016 (Newswire.com) - To meet the demand for mobile devices offering top quality sound - without sacrificing power - Nanyang Technological University (NTU) has invented an ultra-high-quality Class-D amplifier.

Created by NTU’s Division of Electrical and Electronics Engineering in Singapore, the ultra-high-quality chip can tolerate more 'noise' from other components in a device, which reduces distortion so the sound quality can be significantly improved.

In view of the high power-efficiency requirement, virtually all smart mobile devices today use Class-D amplifiers (CDAs) as the driver to the primary loudspeaker.  An ideal Class-D amplifying stage has no distortion and no noise generation in the audible band - and provides close to 100% efficiency. However, in practice, CDAs have imperfections that generate distortion and noise.

To obtain high power efficiency without resorting to a high switching frequency, the team at NTU proposed a novel CDA design, which embodies an input-modulated carrier generator and a phase-error-free, pulse-width modulation (PWM) modulator.

During development, the NTU team used Brüel & Kjær’s PULSE system and Head and Torso Simulator (HATS) to ‘listen’ to the sound from a headset driven by a CDA and then measure the acoustical audio signal.

NTU senior research scientist Ge Tong explained: “This was essentially an integrated circuit design project. The development process started with the schematic design and simulation, followed by layout, parasitic extraction and post-layout simulations.”

The result of this project was unprecedented performance from the CDA. The pinhead-sized chip encompassing the novel CDA design ultimately means that the audio from smartphones will sound like it is coming from high-end stereos, while wireless headphone users will be able to enjoy a longer battery life. Future applications of the chip include audio amplifiers, car audio systems and televisions.

The full article is available to read on Brüel & Kjær’s website.

About Brüel & Kjær

Brüel & Kjær is a world-leading manufacturer and supplier of sound and vibration measurement systems.

We help customers measure and manage the quality of sound and vibration in their products and in the environment. Focus areas are aerospace, space, defence, automotive, ground transportation, airport environment, urban environment, telecom and audio.

Brüel & Kjær has an unparalleled portfolio of sound and vibration equipment and is a long-established designer and manufacturer of innovative instrumentation including sound level meters, microphones, accelerometers, conditioning amplifiers, calibrators, noise and vibration analysers, and PULSE software.

We also design and manufacture the LDS range of vibration test systems, as well as complete airport and environmental monitoring systems: WebTrak, ANOMS, NoiseOffice and Noise Sentinel.

Brüel & Kjær runs a variety of training courses - from basic introductions to noise and its effects to more specialised classes teaching customers how to get the most out of their equipment. Free online training courses, conducted by our expert engineers, run throughout the year too.

Brüel & Kjær is a subsidiary of UK-based Spectris plc, which has annual sales of £1.1bn and employs around 8,300 people worldwide across its four business segments.

Source: Brüel & Kjær