AES Paris 2016
Paper Session P1
P1 - Audio Equipment and Audio Formats
Saturday, June 4, 09:00 — 11:30 (Room 353)
Chair:
Menno van der Veen, Ir. bureau Vanderveen - Hichtum, Netherlands
P1-1 Linearization Technique of the Power Stage in Open-Loop Class D Amplifiers—Federico Guanziroli, STMicroelectroics - Milan, Italy; Pierangelo Confalonieri, STMicroelectroics - Milan, Italy; Germano Nicollini, STMicroelectronics - Milan, Italy
An efficient method to linearize the switching (power) stage of open-loop class D amplifiers is presented. This technique has been successfully applied to an open-loop fully-digital PWM class D amplifier designed in a 40 nm CMOS process leading to nearly 15 dB improvement in the Total Harmonic Distortion (THD). Simulated open-loop class D amplifier performance resulted to 105 dBA Signal-to-Noise Ratio (SNR), and 1W output power over 8 Ohm with 90% power efficiency and 0.014% THD.
Convention Paper 9484 (Purchase now)
P1-2 Physically-Based Large-Signal Modeling for Miniature Type Dual Triode Tube—Shiori Oshimo, Hiroshima Institute of Technology - Hiroshima, Japan; Kanako Takemoto, Hiroshima Institute of Technology - Hiroshima, Japan; Toshihiko Hamasaki, Hiroshima Institute of Technology - Hiroshima, Japan
A precise SPICE model for miniature (MT) triode tubes of high-µ 12AX7 and medium-µ 12AU7 is proposed, based on the physical analysis of the measurement results. Comparing the characteristics between these tubes, the grid current at lower plate voltage and positive grid bias condition is modeled successfully with novel perveance parameters for the first time, though it was known that the perveance depends on both grid and plate bias. It is shown that the modulation factor of the space charge for the MT triodes is different from the other classic tubes. The model is implemented in LTspice to result in a good replication for a variation of three-order magnitude of grid current and cathode current.
Also a poster—see session P5-2
Convention Paper 9485 (Purchase now)
P1-3 Analysis of Current MEMS Microphones for Cost-Effective Microphone Arrays—A Practical Approach—Sven Kissner, Jade University of Applied Sciences - Oldenburg, Germany; Jörg Bitzer, Jade Hochschule Oldenburg - Oldenburg, Germany
With this paper we present a practically relevant investigation of current, commercially available MEMS microphones (Micro-ElectroMechanical Systems). We compared the static noise floor exhibited by single and various parallel MEMS microphone configurations and a conventional and commonly used electret capsule, as well as the directivity patterns of selected configurations. The results suggest that while current types are exhibiting an already acceptable static noise floor, a direct parallel circuit of MEMS microphones allows further reductions of the noise floor close to the theoretical value of 3 dB SPL per doubling of number of microphones while maintaining omnidirectionality below 5 kHz.
Convention Paper 9486 (Purchase now)
P1-4 Matching the Amplifier to the Audio for Highly Efficient Linear Amplifiers—Jamie Angus, University of Salford - Salford, Greater Manchester, UK; JASA Consultancy - York, UK
“Class-D” switching amplifiers are considered to be the most efficient amplifiers available on the market. However, designers must deal with supply rail, and radio frequency interference, as well as the need to switch power devices at high frequencies. Because of these, and other problems, not everyone wishes to use switching based technologies for their amplifiers. Unfortunately, linear amplifiers are significantly more inefficient than switching amplifiers, under sine wave testing. However real audio signals spend much more time at low amplitudes than a sine wave. By changing the switch points for “Class-G” or “Class-H” they can have efficiencies that rival “Class-D” amplifiers producing the same output. The paper develops optimum switch points for both single and multiple switching points, with respect to the expected amplitude distribution of the audio.
Convention Paper 9487 (Purchase now)
P1-5 Delay-Reduced Mode of MPEG-4 Enhanced Low Delay AAC (AAC-ELD)—Markus Schnell, Fraunhofer IIS - Erlangen, Germany; Wolfgang Jaegers, Fraunhofer Institute for Integrated Circuits IIS - Erlangen, Germany; Pablo Delgado, Fraunhofer Institute for Integrated Circuits IIS - Erlangen, Germany; Conrad Benndorf, Fraunhofer Institute for Integrated Circuits IIS - Erlangen, Germany; Tobias Albert, Fraunhofer Institute for Integrated Circuits IIS - Erlangen, Germany; Manfred Lutzky, Fraunhofer Institute for Integrated Circuits IIS - Erlangen, Germany
The MPEG-4 AAC Enhanced Low Delay (AAC-ELD) coder is well established in high quality communication applications, such as Apple’s FaceTime, as well as in professional live broadcasting. Both applications require high interactivity, which typically demands an algorithmic codec delay between 15 ms and 35 ms. Recently, MPEG finalized a new delay-reduced mode for AAC-ELD featuring only a fraction of the regular algorithmic delay. This mode operates virtually at higher sampling rates while maintaining standard sampling rates for I/O. Supporting this feature, AAC-ELD can address even more delay critical applications, like wireless microphones or headsets for TV. In this paper main details of the delay-reduced mode of AAC-ELD are presented and application scenarios are outlined. Audio quality aspects are discussed and compared against other codecs with a delay below 10 ms.
Also a poster—see session P5-3]
Convention Paper 9488 (Purchase now)
