The development of digital microphones and loudspeakers adds new and interesting possibilities of their applications in different fields, extended from industrial, medical to consumer audio markets. One of the rapidly growing field of applications is mobile multimedia, such as mobile phones, digital cameras, laptop and desktop PCs, etc. The advances have also been made in digital audio, particularly in direct digital transduction, so it is now possible to create the all-digital audio recording and reproduction chains potentially having several advantages over existing analog systems.
This paper provides an overview of the effects of timing jitter in audio sampling analog-to-digital converters (ADCs), i.e. PCM (conventional or Nyquist sampling) ADCs and sigma-delta (ΣΔ) ADCs. Jitter in a digital audio is often defined as short-term fluctuations of the sampling instants of a digital signal from their ideal positions in time. The influence of the jitter increases particularly with the improvements in both resolution and sampling rate of today's audio ADCs. At higher frequencies of the input signals the sampling jitter becomes a dominant factor in limiting the ADCs performance in terms of signal-to-noise ratio (SNR) and dynamic range (DR).
In June 2011, Polish Section of the Audio Engineering Society will celebrate its 20th anniversary. On this occasion, the society officers, ending their second, two-year term, present a short summary of the Section's activity during the past four years. The Section's structure comprises the main unit - that is the Polish AES section, and three student sections, associated with the Department of Multimedia Systems at the Gdansk University of Technology, the Chair of Acoustics at the Wroc?aw University of Technology, and the Department of Mechanics and Vibroacoustics at the AGH University of Science and Technology in Cracow. The latter section began its activity only last year. In addition to formal student sections, in the activities of the Polish AES Section also participate students of the Department of Sound Engineering, at the The Fryderyk Chopin University of Music in Warsaw, and students of the Department of Elecroacoustics, at the Warsaw University of Technology.