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Journal of the AES - Table of Contents

2006 March, Volume 54 Number 3



Modulation and System Techniques in PWM and SDM Switching Amplifiers
Malcolm Hawksford   107
Switching amplifiers that use either sigma-delta modulation (SDM) or pulse-width modulation (PWM) can be modeled in terms of linear angle modulation. Distortion generated when applying feedback to PWM is demonstrated, and strategies to improve linearity are then presented. Also, a look-ahead SDM incorporating an energy-balancing binary decision threshold is examined. A unified analytic approach shows that SDM can compete in terms of linearity with PWM power amplifiers and that energy-balancing SDM can achieve similar peak signals.

A Search for Best Error Metrics to Predict Discrimination of Original and Spectrally Altered Musical Instrument Sounds
Andrew B. Horner, James W. Beauchamp, and Richard H. Y. So   140
Knowing the required accuracy of harmonic components in decoded or synthesized periodic audio signals allows a designer to select an optimum strategy. An error metric of spectral accuracy was proposed and evaluated in subjective listening tests. Listeners were asked to discriminate sounds with randomly altered changes in spectral amplitude without any changes in the average spectrum or overall loudness. These tests confirmed the validity of the model.

Advanced Simulation of a Condenser Microphone Capsule
Roger S. Grinnip III   157
An advanced model of a pressure condenser microphone capsule was used to simulate the performance of an experimental prototype. The external acoustic domain was modeled using the boundary-element method, which allowed the capsule to have an arbitrary shape. The results show excellent agreement throughout the measured frequency range. This coupled model was better than the conventional lumped-element techniques.

Bit-Rate Scalable Intraframe Sinusoidal Audio Coding Based on Rate-Distortion Optimization
Richard Heusdens, Jesper Jensen, W. Bastiaan Kleijn, Valery Kot, Omar A. Niamut, Steven van der Par, Nicolle H. van Schijndel, and Renat Vafin   167
A parametric coder based on rate-distortion optimal sinusoid + noise coding of audio and speech signals is presented. The coder minimizes a perceptual distortion measure subject to a bit-rate constraint. A variable-length signal analysis is used to avoid preechoes and to reduce the intersegment correlation. Frequency differential coding is performed to exploit intrasegment correlations. In subjective listening tests using music and speech, this method often performed better than state-of-the-art MPEG-4 audio coders.


AES Standards Committee News   189
ATM networking; digitally-interfaced microphones; microphone specifications; Standards meetings


12th Tokyo Regional Convention Report   190
   Exhibitors   194
   Program   196
120th Convention Preview, Paris   208
   Exhibit Previews   210
Stereophonic Recording Techniques: Old Challenges, New Approaches   225
29th Conference, Seoul, Call for Papers   247
121st Convention, San Francisco, Call for Papers   248


News of the Sections   230
Upcoming Meetings   233
Sound Track   234
Available Literature   236
Membership Information   238
Advertiser Internet Directory   239
In Memoriam   245
Sections Contacts Directory   249
AES Conventions and Conferences   256

FPO For the cover:

2006 March, Volume 54 Number 3

spine: 2006 March, Volume 54 Number 3