Itelco transmitters
Igor Kabo, Vitaliy Stytsko

The Italian company Itelco, one of the world leading developers and manufacturers of terrestrial broadcasting equipment, was founded in 1961. The company has almost 25-year experience in delivery of terrestrial broadcasting equipment to the world market. Its products have been used within many years in more than 110 countries, the number of major equipment installations exceeding 14,000.

The Itelco equipment range includes analog and digital equipment for terrestrial TV broadcasting, microwave stations, and also PC systems for remote control of transmitters' networks.

Analog TV transmitters/transposers series includes transmitters of 1 W...300 kW for VHF I, III and UHF IV, V bands. Standard configurations of the transmitters of up to 30 kW are produced on the solid-state elemental basis. More powerful transmitters have terminal amplifier stages based on tetrode tube or inductive output tube (IOT). The schemes with common and separate amplification of display and sound signals are used. Analog TV transmitters are ready to migration to digital broadcasting by means of replacement or addition of the corresponding amplifier module.

Itelco digital DVB-T 1 kW solid state TV transmitter

Itelco was among pioneers in the field of creation of digital TV and radio broadcasting modern means. Taking part in both the European (DVB-T) and the American (ATSC DTV) terrestrial digital broadcasting equipment projects, the company has made a remarkable contribution into development of these systems. As a result, Itelco was the first to offer its own all-in-one range of digital TV broadcasting equipment of both standards in the world market. The range includes digital amplifiers with integrated COFDM and 8VSB modulators, solid-state TV transmitters of DVB-T and DTV standards with output power of 50 W...30 kW, as well as powerful (10...100 kW) transmitters based on inductive output tubes (IOT). All the digital TV transmitters with output power from 500 W have liquid cooling systems.

Itelco digital DVB-T 100 kW TV re-broadcaster

Digital broadcasting DAB radio transmitters series includes solid-state transmitters of VHF (III) band: air cooled with output power of 100...400 W and liquid cooled with output power of 500 W...1.5 kW. Besides, solid-state air cooled DAB radio transmitters of L band with output power of 50...800 W are produced.

A distinctive feature of all TV and radio broadcasting equipment, manufactured by Itelco, is high reliability, which provides its competitiveness in the market and popularity among the customers. Thus, average time of mean-time-between-failures of a standard transistor power amplifier, defining reliability of the whole transmitter system, makes more than 2.5 years. Transmitters reliability is insured by, first of all, using the most effective circuit techniques and modern technologies during the processes of development and production.

One of the main factors, providing reliability, is the use of high-performance cooling systems. Air cooling is usually used in transmitters with output power of up to 2 kW. Liquid cooling systems are designed for more powerful transmitters. Itelco cooling systems provide optimal temperature mode of the active scheme key-elements, which determines linearity and stability of the transmitter output characteristics, as well as widens the equipments' operating temperature interval, making -30...+50°C, and allows its normal exploitation at up to 4,500 m altitude. The patented design of the liquid cooling system provides unique compactness of its transmitters. Thus, overall dimension of Itelco transmitters, equipped with liquid cooling system, is 40% less than those of transmitters with the same power, equipped with air cooling system, produced by other world leading manufacturers. On the other hand, the liquid cooling system considerably simplifies transmitter's installation and minimizes its maintenance compared with a similar transmitter with air cooling system.

All Itelco transmitters are of module, plug-in-board structure. Each power amplifier module has a stand-alone secondary power feeder with external power fluctuation (within -15...+10%) protection. Besides, each module has a microprocessor, allowing to localize the module's possible malfunction and terminate its effect on the whole transmitter's scheme by means of modules bridging. All the transmitter's microprocessors are joined in a common distributed control and monitoring network. Built-in protection schemes preserve each module from output power overload and reflected power-load, current overload, overvoltage or undervoltage and overheat.

The whole path of transmitters, including exciter, power amplifier, diplexer, and source filter, is based on broadband units. Power amplifiers cover all range of frequencies within VHF (174...230 MHz) and UHF (470...860 MHz) bands. UHF power amplifiers modules are made on lateral two-diffused MOS-transistors (LDMOS), having exclusive linearity, high amplification factor and high power effectiveness. VHF power amplifiers modules are made on field MOS-transistors (MOSFET) having high amplification factor. Each amplification stage ensures nominal output power of about 400 W and amplification of 50 dB.

Amplifiers using digital synthesizers of frequency and filters in the devices with surface acoustic wave allows to supply pitch precision frequency bias with 25 Hz step, and also to get high stability of radiation frequency: not lower than 0,5 x 10-6 per year. Transmitters use compact switched stabilized secondary power supplies providing high stability of system characteristics regardless of supply-line voltage fluctuation. Itelco transmitters are manufactured in any configuration with active or passive stand-by (n+1).

Microprocessor control block provides effective monitoring and control of transmitter parameters. Standard remote control and monitoring interface allow transmitters' reliable exploitation in unattended mode. For this purpose the Itelco Company manufactures ISS special monitoring and control computer system, providing reliable remote control of one transmitter and of the whole network of transmitters, as well as control of the supporting systems operation (stand-alone power supply, fire and intrusion alarm, etc.).

The transmitters' module design and plug-in modules' wide unification allow transmitters' hot-mode quick repair and easy configuration modification (power and band change, transformation into transposers, etc.) by means of replacement or addition of plug-in modules.

Itelco transmitters meet the international standards as for electrical safety, environmental protection, and electromagnetic compatibility. The company's ISO 9001 standard certification ensures high quality of the manufactured equipment.

Provided by Arvex Ltd.

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