AIBD / PRASAR BHARATHI Sub-Regional Workshop on Digital Radio Transmission
This international level workshop was conducted from 3 -11 Dec 2012 at the All India Radio-Staff Training Institute (Technical) complex in New Delhi. It was attended by 14 broadcast engineers and technical personnel from Bhutan, India, Malaysia, Maldives, Mozambique, Nepal, Nigeria and Thailand.
This international level workshop was conducted from 3 – 11 Dec 2012 at the All India Radio-Staff Training Institute (Technical) complex in New Delhi. It was attended by 14 broadcast engineers and technical personnel from Bhutan, India, Malaysia, Maldives, Mozambique, Nepal, Nigeria and Thailand.
The resource persons were senior broadcast engineers from AIR STIT, AIR Headquarters and regional stations, Ministry of Information & Broadcasting and Digital Radio Broadcast companies. The workshop covered theory, practical applications with demonstration and field trips to Digital Radio Transmitter sites and AIR Headquarters.
Participants together with the All India Radio top management and their staff at the entrance of STIT complex
The presentation on Digitalization of the Radio Network in India from the Ministry of Information and Broadcasting gave an insight into the approach made by India and comparing it with other countries. India has a large number of AM, MW and SW transmitters in operation alongside with FM Stereo Transmitters. Digital Radio Mondiale (DRM) is a natural choice especially if simulcast is to be used for a period of time. It was obvious to the international participants that it would be costly and wastage of RF spectrum to let the existing analogue MW and SW transmitters be shut down. To put it simply, the Digital Switch Over technique was a logical step and it must be emphasised here that other countries with large number of AM transmitters are making a similar approach.
The theoretical aspects and practice of Digital Audio standards including the AES/EBU standards, COFDM, Digital Modulation and Channel Coding were presented by various experts from All India Radio. Due to special requests and popular demand, a special lecture on the Galois Field was conducted so that participants can understand advanced codes such as Low Density Parity Check Codes (LDPC), Reed Solomon (RS) and Bose Chaudhiri Hocquenghem (BCH) used in Digital Radio and TV Broadcasting. It was indeed a rare opportunity to learn from a broadcast practitioner as such lectures on this topic are not common and only dealt with by academics at postgraduate level at the Universities.
Digital Radio Transmitter Technology, Antenna and Feeder lines, DRM standards and DRM receivers were also among the topics which generated great interest. It was informative to know which category of analogue AM transmitters could be modified for DRM transmission. The different types of MW and SW antennas with their radiation patterns and antenna feeder lines provided better understanding of the overall digitalization process as not all the participants had previously worked at a radio transmitter site. The DRM field trials conducted by AIR and the problems that arose together with their solutions were presented by the experts directly involved. Evidently proper choice of DRM parameters is essential for clear and robust reception of digital radio signals. It was also reassuring to note that DRM receivers are readily available and the cost would be decreasing as more DRM transmitters start operation. There are already a substantial number of listeners overseas and clear reception is obtainable in countries as far away as the United Kingdom.
Mr I. I. George, Deputy Director General, delivering a presentation on Antennas & Feeder line
Other digital radio standards including DAB, DAB+, HD Radio and of course DRM+ were also introduced. The differences were explained and it is apt to say that the participants were able to distinguish between the technical features and specifications of each standard and their applications.
The participants were taken on a visit to the New Broadcasting House at New Delhi which was AIR Headquarters. Senior Engineers were at hand to explain the set up of radio studio and transmission facilities and equipment. One of the most remarkable features is the satellite links from New Delhi and to all major cities in India which are coordinated at this building. India is classified as a sub continent with an extremely huge land mass and a large population speaking many different languages. Satellite links are necessary to bring the Indian population from vast distances together and the broadcast personnel must have sufficient knowledge and expertise to operate the station. Needless to say, the equipment is sophisticated and it is continuously upgraded to take advantage of recent advances in digital satellite technology and the shift from Single Carrier Per Channel (SCPC) to Multi Carrier Per Channel (MCPC) operation.
A field trip was made to the AIR Transmitter site at Khampur where both MW and SW Transmitters are located. Again, experienced broadcast personnel were at hand to explain the operation of the DRM Transmitter, Antennas and feeder lines. Within the STIT complex itself, a DRM Tx is also located and further opportunity presented itself when digital measurements were carried out by the course coordinator, Mr K Murugan. Both the field trip to AIR Khampur and the DRM measurement exercise carried out at the STIT site provided the practicals that complemented the theoretical aspects explained during the lectures.
Mr V.K.Balaeja, Director Engineering, AIR, Khampur complex explaining the practical operation of the DRM Transmitter
The workshop was well organised and took into account both the theoretical and practical aspects of Digital Radio Transmission. The resource persons were trained experts in their own field and went out of their way to make the course a success. The Ministry of Information & Broadcasting, India is extended a sincere appreciation of thanks as its officials had also contributed by providing the necessary support and approval while AIBD is commended for the coordination between the various countries and AIR to launch this joint activity. A special note of thanks to Prahabindra Das, Director, International relations at AIR for his efforts in getting local approvals to host this activity. Last but not the least the efforts of K Murugan, who served as both the course coordinator and resource person is given due credit for taking great care for ensuring the smooth implementation of the workshop proceedings which contributed to its success.
Mr N A Khan, Additional Director General, AIR-Staff Training Institute Technical with K Murugan Director AIR & Course Coordinator presenting the certificates to the participants after the closing ceremony
By V. Jeewa, M.Eng, C.Eng, Deputy Director & Zarah Naumul B.Eng
Tun Abdul Razak Broadcast & Information Institute,
Ministry of Information, Communication & Culture, Malaysia