What is the Radio ?

Radio is the wireless transmission of signals, by modulation of electromagnetic waves with frequencies below those of visible light.

Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space. It does not require a medium of transport. Information is carried by systematically changing (modulating) some property of the radiated waves, such as their amplitude or their frequency. When radio waves pass an electrical conductor, the oscillating fields induce an alternating current in the conductor.

The word 'radio' is used to describe this phenomenon, and television, radio, and cell phone transmissions are all classed as radio frequency emissions.

Modulation is the process where speech, music and the like are impressed onto the carrier wave of a transmission. Detection or demodulation is the reverse proces which takes place in a receiver. The speech, music etc is recovered and may then be amplified and applied to an ear piece or a loud speaker. The most common forms of modulation are Amplitude Modulation (AM) and Frequency Modulation (FM) both of which use different modulation and detection circuits. Cell phones, digital radio and digital television use more complex modulation and demodulation systems.

The simplest AM receiver is the Crystal Set or Crystal Radio. Demodulation is achieved by a semiconductor diode. One of the earliest forms of detection consisted of a thin copper wire in contact with a small chunk of Galena Rock. Adequate signals could be heard in headphones for up to 50 km with simple arrangements.

source 

Read more ...

Posted by bedegar |

what is "Streaming" ?

Streaming technology is used to distribute Internet radio, typically using a lossy audio codec. Streaming audio formats include "MP3, Ogg Vorbis, Windows Media Audio, RealAudio, and HE-AAC (or aacPlus)".^[1] Audio data is continuously transmitted serially ("streamed") over the local network or internet in TCP or UDP packets, then reassembled at the receiver and played a second or two later. The delay is called lag, and is introduced at several stages of digital audio broadcasting.

translate indonesia :

Teknologi streaming digunakan untuk mendistribusikan radio internet, biasanya menggunakan lossy audio codec. Format audio streaming termasuk "MP3, Ogg Vorbis, Windows Media Audio, RealAudio, dan HE-AAC (atau aacPlus)". [1] Data Audio terus ditransmisikan serial ("streaming") melalui jaringan lokal atau internet di TCP atau UDP paket, kemudian disusun kembali pada penerima dan bermain satu atau dua detik kemudian. Penundaan ini disebut lag, dan diperkenalkan pada beberapa tahap penyiaran digital audio.












source

Read more ...

Posted by bedegar |

Internet radio, web radio, net radio, streaming radio, e-radio

Internet radio (also web radio, net radio, streaming radio, e-radio) is an audio service transmitted via the Internet. Music streaming on the Internet is usually referred to as webcasting since it is not transmitted broadly through wireless means.

Internet radio involves streaming media, presenting listeners with a continuous stream of audio that cannot be paused or replayed, much like traditional broadcast media; in this respect, it is distinct from on-demand file serving. Internet radio is also distinct from podcasting, which involves downloading rather than streaming. Many Internet radio services are associated with a corresponding traditional (terrestrial) radio station or radio network. Internet-only radio stations are independent of such associations.

Internet radio services are usually accessible from anywhere in the world—for example, one could listen to an Australian station from Europe or America. Some major networks like Clear Channel (which has been already lifted the overseas restriction of online streaming), CBS Radio and Citadel Broadcasting (except for news/talk and sports stations) in the US, and Chrysalis in the UK restrict listening to in country because of music licensing and advertising concerns.^{[citation needed]} Internet radio remains popular among expatriates and listeners with interests that are often not adequately served by local radio stations (such as eurodance, progressive rock, ambient music, folk music, classical music, and stand-up comedy). Internet radio services offer news, sports, talk, and various genres of music—every format that is available on traditional radio stations.

 wikipedia.org

Read more ...

Posted by bedegar |

Stream processing

Stream processing is a computer programming paradigm, related to SIMD (single instruction, multiple data), that allows some applications to more easily exploit a limited form of parallel processing. Such applications can use multiple computational units, such as the FPUs on a GPU or field programmable gate arrays (FPGAs)^[1], without explicitly managing allocation, synchronization, or communication among those units.
The stream processing paradigm simplifies parallel software and hardware by restricting the parallel computation that can be performed. Given a set of data (a stream), a series of operations (kernel functions) are applied to each element in the stream. Uniform streaming, where one kernel function is applied to all elements in the stream, is typical. Kernel functions are usually pipelined, and local on-chip memory is reused to minimize external memory bandwidth. Since the kernel and stream abstractions expose data dependencies, compiler tools can fully automate and optimize on-chip management tasks. Stream processing hardware can use scoreboarding, for example, to launch DMAs at runtime, when dependencies become known. The elimination of manual DMA management reduces software complexity, and the elimination of hardware caches reduces the amount of die area not dedicated to computational units such as ALUs.

Read more ...

Posted by bedegar |