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Realistic sound rendering can directly impact the perceived realism of users of interactive media applications. An accurate acoustic response for a virtual environment is attuned according to the geometric representation of the environment. This response can convey important details about the environment, such as the location and motion of objects. The most common approach to sound rendering is a two-stage process: Sound propagation: the computation of impulse responses (IRs) that represent an acoustic space. Audio rendering: the generation of spatialized audio signal from the impulse responses and dry (anechoically recorded or synthetically generated) source signals.

Analog Devices, Inc., has introduced a pair of Class-D audio amplifiers for smart phones, GPS units and other handheld electronics where premium sound quality offers a major competitive advantage. The SSM2375 and SSM2380 amplifiers provide audio system designers with the option of fixed or programmable gain settings combined with low noise and superior audio performance. The SSM2380 low-power, stereo Class-D amplifier is the first in its class to incorporate an I²C interface, which allows gain stages to be set from 1 dB to 24 dB (plus mute) in 47 distinct steps with no other external components required. The programmable interface also enables independent L/R channel shutdown, a variable low-EMI (electro-magnetic interference) emission control mode, and programmable ALC (automatic level control) functions for speaker protection. The SSM2380 achieves a 100-dB SNR (signal-to-noise ratio) and extends battery life by achieving 93 percent power efficiency at 5 V while running at 1.4 W into an 8-ohm speaker.

Part 5 of an excerpt from the book "Acoustics and Psychoacoustics," fourth edition, begins with a brief look at noise-reducing headphones and "mosquito" units and ringtones, and then delves into the ins and outs of audio coding systems.

A new triple-rate (3G/HD/SD) audio/video clock generator from National Semiconductor Corp., eliminates the need for external clock conditioning in professional and broadcast video equipment. The LMH1983 produces all the major video and audio reference clocks required for a broad range of applications. The highly integrated LMH1983 also provides the industry’s lowest-output jitter (40 ps peak-to-peak), enabling Society of Motion Picture and Television Engineers (SMPTE) compliance using field-programmable gate array (FPGA) SerDes transceivers.

This article discusses the requirements, constraints and challenges in creating high-quality musical instruments using electronic components (both analog and digital) available today.

Verification of algorithm-intensive systems is a long, costly process. Studies show that the majority of flaws in embedded systems are introduced at the specification stage, but are not detected until late in the development process. These flaws are the dominant cause of project delays and a major contributor to engineering costs. For algorithm-intensive systems —including systems with communications, audio, video, imaging, and navigation functions— these delays and costs are exploding as system complexity increases. It doesn't have to be this way. Many designers of algorithm-intensive systems already have the tools they need to get verification under control. Engineers can use these same tools to build system models that help them find and correct problems earlier in the development process. This can not only reduce verification time, but also improves the performance of their designs. In this article, we'll explain three practical approaches to early verification that make this possible. First, let's examine why the current algorithm verification process is inefficient and error-prone. In a typical workflow, designs start with algorithm developers, who pass the design to hardware and software teams using specification documents.

The ARM Cortex™-M4 processor is the latest embedded processor by ARM specifically developed to address digital signal control markets that demand an efficient, easy-to-use blend of control and signal processing capabilities. The combination of high-efficiency signal processing functionality with the low-power, low cost and ease-of-use benefits of the Cortex-M family of processors is designed to satisfy the emerging category of flexible solutions specifically targeting the motor control, automotive, power management, embedded audio and industrial automation markets. The Cortex-M4 processor features extended single-cycle multiply-accumulate (MAC) instructions, optimized SIMD arithmetic, saturating arithmetic instructions and an optional single precision Floating Point Unit (FPU). These features build upon the innovative technology that characterizes the ARM Cortex-M series processors…

Given the maturity of MOSFETs, selecting one for your next design may seem deceptively simple. Engineers are familiar with the figures of merit on a MOSFET data sheet. Selecting a MOSFET requires the engineer to use their expertise in scrutinizing different specifications for individual applications. In an application such as a load switch in a server power supply, the switching aspects of a MOSFET matter little because the MOSFET is on almost 100% of the time. The on resistance (RDS(ON)) may be the key figure of merit in such an application. Still other applications, including switching power supplies, use MOSFETs as active switches, and cause the engineer to value other MOSFET performance parameters. Let us consider some applications and their prioritization of MOSFET specifications.

The consumer handheld market is growing by leaps and bounds. With more processing power and increased support for more applications, portable products are cross-pollinating with traditional computing systems even as the product life cycle has decreased considerably in this market segment. As a result, especially in this era of economic slowdown, it is imperative that new products meet the time-to-market window to gain maximum acceptance. A decrease in product life cycles requires a reduced development cycle and an increased emphasis on reusability and reprogrammability. The emerging handheld market is also seeing interesting trends in which each individual device in a family has lower volumes but there is more customization across the series of devices, effectively upping the total unit volumes. The key challenge then becomes how to develop a system that is widely reusable and also customizable. These requirements have led designers increasingly to turn to the FPGA for handheld-product development. The FPGA has become more powerful and feature-rich, while gate counts, area and frequency have increased. FPGA development and turnaround cycles are considerably shorter than those of custom ASICs, and the added advantage of reprogrammability can make the FPGA a more compelling solution for handheld embedded systems.