No abstract

No abstract

This study presents a novel spatial audio coding (SAC) technique, called analysis by synthesis SAC (AbS-SAC), with a capability of minimising signal distortion introduced during the encoding processes. The reverse one-to-two (R-OTT), a module applied in the MPEG Surround to down-mix two channels as a single channel, is first configured as a closed-loop system. This closed-loop module offers a capability to reduce the quantisation errors of the spatial parameters, leading to an improved quality of the synthesised audio signals. Moreover, a sub-optimal AbS optimisation, based on the closed-loop R-OTT module, is proposed. This algorithm addresses a problem of practicality in implementing an optimal AbS optimisation while it is still capable of improving further the quality of the reconstructed audio signals. In terms of algorithm complexity, the proposed sub-optimal algorithm provides scalability. The results of objective and subjective tests are presented. It is shown that significant improvement of the objective performance, when compared to the conventional open-loop approach, is achieved. On the other hand, subjective test show that the proposed technique achieves higher subjective difference grade scores than the tested advanced audio coding multichannel.

No abstract

Closed-loop spatial audio coding is a compression technique, developed based on MPEG Surround (MPS) standard, having an advantage of minimising distortion due to quantisation process of spatial parameters. Despite the MPS is developed based on filterbank, however, this closed-loop system performs better on Modified Discrete Cosine Transform (MDCT). Considering its high performance over the open-loop system, this paper presents further investigation on objective performance of closedloop spatial audio coding against various quantisers of spatial parameters. Experiments have been conducted to measure signal to noise ratio (SNR) across different types of uniform spatial quantisers at various operating bitrates. The results show that the SNR achieved by the open-loop approach is strongly affected by the type of the quantiser while, in contrast, the SNR achieved by the closed-loop approach is relatively constant regardless the number of bits used in the quantisers. Moreover, the results also show that the closed-loop configuration can consistently improve SNR in any quantisation scheme.

Market demands on a more impressive entertainment media have motivated for delivery of three dimensional (3D) audio content to home consumers through Ultra High Definition TV (UHDTV), the next generation of TV broadcasting, where spatial audio coding plays fundamental role. This paper reviews fundamental concept on spatial audio coding which includes technology, standard, and application. Basic principle of object-based audio reproduction system will also be elaborated, compared to the traditional channel-based system, to provide good understanding on this popular interactive audio reproduction system which gives end users flexibility to render their own preferred audio composition.

Since the Federal Communication Commission (FCC) issued a license for the 3.1 – 10.6 GHz frequency spectrum for unlicensed radio applications, many papers have been published regarding ultrawideband (UWB) antenna design. The issue of UWB antenna design is determining how to create an antenna with a wide bandwidth, capable of rejecting communication systems that coexist with UWB bands, and capable of designing UWB antennas for multiple input multiple output (MIMO) communication system applications. This study examines the design of UWB antennas with monopole and slot types based on evaluations published over the last two decades. The discussion began with UWB and MIMO systems and then moved on to the configuration of monopole and slot UWB antennas. UWB antenna layout with notched bands and the several types of notched bands available. Finally, two port and quad-port MIMO antenna configuration is examined. To further understand UWB antenna design, numerous UWB antenna configurations are simulated. The outcomes of this review can be utilized as preliminary reading material for researchers looking into UWB antennas.

No abstract