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The main advantage of such digital broadcasting is that it yields sound quality comparable to FM, but over shortwave distances. As a digital medium, DRM can also transmit other digital data besides digitized music, including text, pictures and computer programs. DRM has been designed especially to use older transmitters designed for audio AM, so major new investments are not required for early transmissions. The encoding and decoding can be performed with digital signal processing, so that small computers added to a conventional transmitter and receiver can perform the rather complex encoding and decoding.
The organisation has recently received approval for the AM standard from the IEC, and the ITU has approved its use in most of the world. Approval for the Americas ( ITU region 2) is pending amendments to other existing international agreements. The inaugural broadcast took place on June 16, 2003, in Geneva, Switzerland, at the ITU's annual World Radio Conference .
Unlike the PACPerceptual Audio Coding PAC is an algorithm, like MPEG's MP3 standard, used to compress digital audio by removing extraneous information not perceived by most people. It is used by Sirius Satellite Radio for their DARS service, and iBiquity has been testi compression algorithm currently used by iBiquityiBiquity is a company formed by the merger of USA Digital Radio and Lucent Digital Radio, with the goal of creating an in-band on-channel digital radio system for the United States.'s IBOC system in the United StatesThe United States of America also referred to as the United States U. America ¹ or the States is a federal republic in central North America, stretching from the Atlantic in the east to the Pacific Ocean in the west. It shares land borders with Canada in, DRM's system uses MPEG-4MPEG-4 introduced in 1998, is the designation for a group of audio and video coding standards agreed upon by MPEG (Moving Picture Experts Group). MPEG-4 is primarily designed to handle low bit rate content, from 4800 bit/s to approximately 4 Mbit/s. The p to code the audio: AACAdvanced Audio Coding AAC is a lossy data compression scheme intended for audio streams. AAC was designed to replace MP3. AAC, ISO/IEC 13818-7, is an extension of the MPEG-2 international standard, ISO/IEC 13818-3. It was further improved in MPEG-4, MPEG- for music and CELP or HVXC for speech programs. All codecs can optionally be combined with SBR. The resulting low- bitrate digital information is modulated using COFDM, similar to iBiquity's signal. Both systems can run in hybrid mode, with both analogue and digital, or in all-digital mode. iBiquity has been tested only on mediumwave AM with 10 kHz channel spacing ; however, DRM has also been tested successfully on shortwave and longwave, and with 9 kHz channel spacing as well.