Based on rain gauge and radar measurements carried out in Malaysia and Amazon region (Brazil), this paper deals with the description of meteorological factors affecting the radio wave propagation in low latitude areas. As it will be shown along the paper, in spite of the large geographical separation between these two countries similar results have

This paper provides a historical perspective on communication studies in Malaysia since its beginning in 1970. Government policies and support in addition to institutional factors shaped the development of communication education in Malaysia. History is important for scholars of communication to understand the foundations and influences that have s

Multiplexing techniques are broadly classified as analogue and digital, digital being the latest. Time Division Multiplexing (TDM) and Statistical TOM are most commonly used digital multiplexing techniques. The TOM is a detenninistic method of multiplexing various sources in pre-determined fixed slots. Statistical TDM, (STDM) uses dynamic method of

The main area of speech coding standards is digital telephone, cellular mobile digital radio, and satellite fixed, and mobile system. Various digital speech coding standards which are currently in use and others are being developed for such applications. Most of these standards are International Telecommunication Union (lTU) based recommendations,

All communication channels transmit infonnation fonn one user to another using channel bandwidth mostly measured in bits/second. With the advent of latest technological tools, the bandwidth efficiency of all the channels may be enhanced beyond their normal transmission capability; mean more bits can be transmitted through the same channel. Techniqu

In recent years much work has be concentrated on encoding speech. Various coding methods are developed such as Low-Delay Codebook Excited Linear Prediction (LD-CELP), Codebook Excited Linear Prediction (CELP), Pulse Residual Excited Linear Prediction (PRELP) and others. These encoders operate at very low bit rates (4.8Kbps) as well as maintained sp

In multiplexing many sources are combined in a common channel to maximise the bandwidth of the system. There can be many components of the STDM such as compressed speech sources at lower rates, voice activity detectors and lost frames reconstruction. This chapter briefly explains all three major components for the under lying multiplexer architectu

Linear Predictive Coding (LPC) is a mathematical (signal processing) technique used to remove the redundancy from speech signals. To remove the redundancy from speech signal, is done in 1\vo stages, first stage is to remove short term correlations form the signal and the second is to remove long term correlations. The short term and long term redun

In standard Codebook Exited Linear Coding (CELP) the encoding method uses random values for excitation vectors. The excitation is modelled by the codebook. Each time a segment of speech is encoded and an excitation vector is matched to minimise the error between original and encoded signal to maintain quality of speech. This chapter narrates the CE

Discontinuous Transmission (DTX) is a concept used in some mobile standards, mostly in Groupe Special Mobile (GSM) systems. In DTX systems, Voice Activity Detection (VAD) and comfort noise are essential element. The usage of DTX in the systems allo\vs transmissions during activity periods and remains silent during non-activities. This chapter is de